CSS HTML Validator - The fast, all-in-one, HTML, CSS, Link, SEO, spelling, and accessibility checker for Windows, & htmlval for Mac and Linux
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Frequently Asked Questions and Answers (FAQ)

Top FAQs (most popular)

Install/Uninstall Issues

Starting Issues (after Installation)

Registration and Licensing

Interface (GUI) Issues

Runtime Issues

Printing Issues

Validation Issues

Configuring the Validator

Batch Processing/Validating

Link Checking

Using the Included Tools

Features

Operating System Related

Miscellaneous Issues

Legacy Issues (Applies to Obsolete Versions)


Install/Uninstall Issues

I can't install the program. It tells me the file is corrupt.

Check your computer for viruses and malware! The most likely cause of this is a virus infecting the EXE that you have downloaded. When you run the CSS HTML Validator setup program, it detects the corruption and lets you know about it. If you don't find any viruses or malware on your computer then try downloading the file again. Also, make sure the file that you get is digitally signed by AI Internet Solutions LLC.


How do I do a silent install?

You can use the following arguments when running the setup program:

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I'm upgrading to a new computer. How do I move HTML Validator over to it?

You should download the latest version of HTML Validator and install it using the setup program. Simply copying the files over will not perform a correct installation. After installing it, you can register it with your registration information.

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I uninstalled a previous version of HTML Validator and am having problems using the new version.

If you have two versions of HTML Validator installed, then uninstalling one of them may interfere with the other. You should reinstall (into the same folder) the version that you want to keep using after uninstalling another version of HTML Validator that was also on your system.

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How do I remove the HTML Validator option settings from the registry?

WARNING! This removes your HTML Validator option settings from the registry! You should reinstall HTML Validator after doing this if you want to continue using HTML Validator. You may have to do this procedure for every user that you want the option settings removed for. You should also execute/open the *.reg file at least once as administrator because there is a certain key that should be removed that requires administrator access to remove.

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How do I replicate the configuration and options for multiple installs?

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I'm having trouble with an upgrade installation. How do I do a clean install?

  1. Close CSS HTML Validator so that it is not running.
  2. Uninstall all versions of CSS HTML Validator from your computer. You can use Uninstall a program (or Add or Remove Programs) in the Control Panel. If at uninstall you are asked to do a "full uninstall", then answer 'Yes'. If this question is asked and you answer 'yes' then you do not need to follow the link in the next step to remove the old option settings from the registry.
  3. (if you did not answer 'yes' to a full uninstall) Remove old option settings from the registry (this will cause your CSS HTML Validator options and registration information to be forgotten so you can start fresh).
  4. (optional) For an even cleaner install, you can manually delete the HTML Validator folders where you originally installed CSS HTML Validator. These are usually folders beginning with HTMLValidator in your C:\Program Files (x86) or C:\Program Files folder (like C:\Program Files\HTMLValidator220). Normally this step is not necessary.
  5. Install the version of CSS HTML Validator that you want to use (we always recommend the latest version).
  6. Run and then register CSS HTML Validator using your registration information.

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How do I install the latest version without uninstalling an older version?

To avoid potential conflicts, we recommend uninstalling a previous version before installing a new major version (this includes major upgrades like v17 to v18, 2020/v20 to 2022/v22, etc. but does not include minor updates such as from v19.02 to v19.03 or from v21.00 to v21.01). With current versions, you can install it with a previous version on your system. If you do this, please note the following:

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Starting Issues (after Installation)

HTML Validator does not start (does nothing when trying to start).

This is often caused by an overreacting security program that is running in the background. Try temporarily disabling any security software and then running the program. Also, see if you can create an exception for CSS HTML Validator in any security software that may be blocking the program from running.

Two program that have, in some cases, been known to block CSS HTML Validator from starting are F-Secure and Zone Alarm. For a list of other programs that have been reported to cause problems and for some possible solutions, please see the forum topic about known issues with 3rd Party Software.

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HTML Validator displays the error "HTML Validator: Error Opening HTML Configuration."

In CSS HTML Validator, go to Options > Validator Engine Options > Validator Engine Options or press Ctrl+F4 and then go to the Validator Engine > Config File page. Make sure that the default configuration file contains a FULL and correct path to the configuration file. For example, it should be something like C:\Users\(username)\AppData\Roaming\AI Internet Solutions\CSS HTML Validator\19.0\htmlvalV190.cfg or C:\Users\(username)\AppData\Roaming\AI Internet Solutions\CSS HTML Validator\22\htmlvalV220.cfg depending on the version that you're using.

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HTML Validator cannot load the Tag Inserter Configuration.

Using regedit.exe, delete TagInserterConfigFileVXXX in the key HKEY_CURRENT_USER\Software\AI Internet Solutions\CSE HTML Validator v4\Editor\Options. This will cause HTML Validator to reset this value to the default value which will likely fix the problem. If this doesn't work, and you have manually changed the Tag Inserter Configuration, then make sure that it is in the correct format or HTML Validator will not be able to load it.

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HTML Validator freezes when trying to start.

This may happen if you have disconnected network drives. Check to make sure that you have no disconnected network drives and then try to restart HTML Validator. If this doesn't work, try using regedit.exe to delete SelectedFolder and SelectedFolder2 (if it exists) in the key HKEY_CURRENT_USER\Software\AI Internet Solutions\CSE HTML Validator v4\Editor\Interface and then restart HTML Validator.

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Registration and Licensing

I lost my license key and/or need to download the program again.

You can have all your registration information and license keys emailed to you again, including information on how to download a registerable version. Send Registration Information

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Can I buy one license and install HTML Validator on two computers?

If you have two computers (such as a desktop and notebook) and you are the only user of both computers then you can buy only one license and use it on both computers.

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I'm not getting the email with my registration information.

First, make sure that your registration information and license keys have been emailed to you. If you do not receive it within 24 hours (although normally it comes much faster), then the most likely cause is a spam filter that is incorrectly filtering or blocking the email. You may need to address this with your spam filtering software to make sure that the email is not being discarded or incorrectly sent to the wrong folder.

If the above doesn't resolve the problem or you do not use spam filtering software or spam filtering rules on your computer, then your email service provider or ISP may be filtering or blocking the email. If you do not receive your registration information email within 24 hours after it is sent then we recommend that you contact your email service provider or ISP and ask them why you are not receiving email from htmlvalidator.com.

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How can I automatically register HTML Validator by entering information directly into the registry?

For CSS HTML Validator Std/Pro/Enterprise 2019/v19, you can install these string value names: RegistrationKeyV190, RegistrationNameV190, and RegistrationPINV190 in HKEY_CURRENT_USER\Software\AI Internet Solutions\CSE HTML Validator v4.

For CSS HTML Validator Home/Pro/Enterprise 2020/v20, you can install these string value names: RegistrationKeyV200, RegistrationNameV200, and RegistrationPINV200 in HKEY_CURRENT_USER\Software\AI Internet Solutions\CSE HTML Validator v4.

For CSS HTML Validator Home/Pro/Enterprise 2021/v21, you can install these string value names: RegistrationKeyV210, RegistrationNameV210, and RegistrationPINV210 in HKEY_CURRENT_USER\Software\AI Internet Solutions\CSE HTML Validator v4.

For CSS HTML Validator Home/Pro/Enterprise 2022/v22, you can install these string value names: RegistrationKeyV220, RegistrationNameV220, and RegistrationPINV220 in HKEY_CURRENT_USER\Software\AI Internet Solutions\CSE HTML Validator v4.

See also: how to stop HTML Validator from requiring registration for different user accounts

NOTE: If running under Wine then you can run "wine regedit" from the terminal to edit Wine's registry.

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How can I stop HTML Validator from requiring registration for different user accounts?

HTML Validator stores registration information in the registry under HKEY_CURRENT_USER. Therefore, it needs to be registered under each user account that will use it.

For v11.0x and above, this requirement can be overridden by creating new string values in the registry named RegistrationNameV220, RegistrationKeyV220, and RegistrationPINV220 under HKEY_USERS\.DEFAULT\Software\AI Internet Solutions\CSE HTML Validator v4 (be sure to use "v4" even if using a later version). The same is true for other versions, but replace "V220" in the value names with the correct version: "V170" for v17, "V180" for 2018/v18, "V190" for 2019/v19, "V200" for 2020/v20, "V210" for 2021/v21, "V220" for 2022/v22, etc. Store the value names and string values in HKEY_USERS\.DEFAULT\Software\AI Internet Solutions\CSE HTML Validator v4. The values should be your registration name, key, and PIN number as given in your license information.

Note that each user account will still have its own options and settings (they will not be shared among accounts).

Below is an example .reg file for 2022/v22 that you can copy, paste, and save (i.e. as chv-license.reg) and fill in your license details by changing the empty strings to strings that are the proper values (name, key, and PIN). Save the file then execute it (i.e. double-click it) and the Registry Editor should add the registry entries to your registry (administrator privileges will be required to add these keys).

Windows Registry Editor Version 5.00 [HKEY_USERS\.DEFAULT\Software\AI Internet Solutions\CSE HTML Validator v4] "RegistrationNameV220"="" "RegistrationKeyV220"="" "RegistrationPINV220"=""

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My registered version of HTML Validator is acting like it is the trial version.

First, make sure that you have downloaded a registrable version of HTML Validator using your registration number and PIN number (the trial version cannot be registered). Then install it and enter your registration information into the program (Help > Register Program) according to the instructions provided when you purchased the license. Make sure that you enter the correct registration information into HTML Validator and that you use the correct key for the version of HTML Validator that you are using. A common problem is using an old key that was for a previous version of HTML Validator. You can also have your registration information (with the latest keys) sent to you again.

If the above doesn't work, then another possible cause of this problem is when there is an old or trial version of csevalidator.dll still on your hard drive after you install the registered version. Search your computer for csevalidator.dll and delete all copies of it except the copy in the Windows system folder. This file should only be in the Windows system folder. If this doesn't work, make sure that HTML Validator is not running and use the setup program to reinstall HTML Validator into the same folder as the original installation.

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How can I see the license agreement?

The license agreement is included with all versions of CSS HTML Validator. It's also included in the documentation of CSS HTML Validator. See also the current license agreement in the online version of the documentation.

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Interface Issues

HTML Validator is unstable, crashes, or exhibits unusual GUI behavior.

First, make sure that you are using the latest version of CSS HTML Validator by doing an update check (choose Help > Check for Updates in the editor). You can also see what version you are using by choosing Help > About and comparing it to the latest version available for download. If you think you've found a bug, are using the latest version, and can consistently reproduce the bug, then please contact us.

Other possible causes of this are bad hardware (such as defective memory), running too many programs in the background, and running software that interferes with the normal operation of your computer. You may also want to try updating your video drivers, as bugs in video drivers have been known to cause system and application crashes.

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Runtime Issues

HTML Validator freezes (stops responding) while trying to load or reload a document (or for unknown reason).

If using CSS HTML Validator 2019/v19 then make sure you're using v19.0011 or above. If that doesn't fix the problem and you're using Windows 10 Version 1803 then update Windows 10 to a newer version/build, like 1809 or above, or apply all the latest updates for 1803. To find out what version of Windows you have, press Win+R and run "winver".

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How do I change the sound that is played at the end of a validation?

You can specify what sounds you want to play in the Validator Engine Options > Sound page, as well as enable and disable sounds.

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How to I change the default folder when opening a file?

For the Home/Standard or professional edition: HTML Validator normally uses the folder selected in the Resource Window, Shell tab as the default folder when opening files. To change the selected folder, view the Resource Window, select the Shell tab, and then select the folder that you want to be the default in the top half of the Resource Window.

For the Lite edition (v7.0+): The "Start in" folder can be changed (by editing the properties of the shortcut used to launch CSS HTML Validator Lite) to the folder that you'd like to be the default folder when first opening a file with File > Open. CSS HTML Validator Lite will also remember the directory of the last opened file until the program is closed.

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Printing

I got a printing error when trying to print.

Please exit CSS HTML Validator and then delete the registry key PrinterOptionsV1101 in HKEY_CURRENT_USER\Software\AI Internet Solutions\CSE HTML Validator v4\Editor\Options.

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Validation Issues

The validator is telling me that not all of my tags are closed. How do I find out which tags are not closed?

It is normal for some tags not to be closed (have end tags). For example, the <img> and <meta> tags should not have end tags. If a tag that should be closed is not closed then the validator will point it out with an error message. If it is acceptable for a tag not to have an end tag then the validator will not generate any error or warning messages and will not tell you specifically which tags are not closed.

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Why is the validator telling me that some of my tags are not closed (have no end tag) when the end tags are there?

The most likely cause of this is that there is a mismatched quotation mark in a tag, either an extra one or a missing one. This is confusing the parser and the validator is not able to see the end tags that are there. To find the problem, look for the first message that starts with "Reached the end of the line before a closing quote..." or "This line contains part of a quoted string that spans more than one line...". The mismatched quotation mark is probably on or near that line.

See also: What do the messages "Reached the end of the line...", "This line contains part of a quoted string that spans more than one line...", and "Reached the end of the document before..." mean?

Important: If you don't receive any "Reached the end of the line before a closing quote..." or "This line contains part of a quoted string that spans more than one line..." messages, then you may have the Allow multi-line quotes option checked. You may want to go to the Validator Engine Options and uncheck this option so that "Reached the end of the line before a closing quote..." and "This line contains part of a quoted string that spans more than one line..." messages can be generated, thus making it easier to find certain problems caused by improper quotations. We recommend that you keep this option unchecked.

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What do the messages "Reached the end of the line...", "This line contains part of a quoted string that spans more than one line...", and "Reached the end of the document before..." mean?

The "Reached the end of the line before a closing quote..." or "This line contains part of a quoted string that spans more than one line..." message could indicate two things: 1) You have a quoted string on multiple lines or 2) there is a missing or extra quotation mark. If #1, then we recommend that you put the whole quotation on one line and do not wrap it onto multiple lines. If #2, then you should look for an extra or missing quotation mark in the line that causes the first "Reached the end of the line before a closing quote..." or "This line contains part of a quoted string that spans more than one line..." message to appear.

The "Reached the end of the document before..." message is sometimes displayed when there is a mismatched quotation mark somewhere in the document. The mismatched quotation mark may make HTML Validator think that your HTML tags are in a quoted string, so it ignores them. This can cause HTML Validator to generate erroneous messages. To find where the problem is likely to be, look at the first line that causes the "Reached the end of the line before a closing quote..." or "This line contains part of a quoted string that spans more than one line..." message to appear. Look at this line to make sure that you have not misused any quotation mark characters by forgetting to include one or by using an extra quotation character.

Important: If you don't receive any "Reached the end of the line before a closing quote..." or "This line contains part of a quoted string that spans more than one line..." messages, then you may have the Allow multi-line quotes option checked. You may want to go to the Validator Engine Options and uncheck this option so that "Reached the end of the line before a closing quote..." and "This line contains part of a quoted string that spans more than one line..." messages can be generated, thus making it easier to find certain problems caused by improper quotations. We recommend that you keep this option unchecked.

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Why is my "a" tag out of range?

It is likely that a previous "a" start tag was not ended. "a" elements cannot be nested, even if it is just a <a name="(name)"> tag. All <a> start tags must end with </a>.

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How do I print or email a validation report?

If your edition supports the Batch Wizard, then you can use it to generate a validation report in HTML for single or multiple documents. The report can then be printed from your web browser. To do this, you can simply use the Validate with Batch Wizard function (Shift+F6) from the integrated editor. Otherwise you will have to go into the Batch Wizard and create a target list with the documents that you want to validate.

You can also choose Copy Messages to Clipboard from the context menu (right-click menu) of the Results Window. You can then paste the messages somewhere where they can be printed, such as a blank document in HTML Validator, or you can paste the messages into an email. Similarly you can choose Links > Export Links to Text in the context menu to generate a list of links that can be printed or emailed. To print the structure, choose Print from the context menu of the memo where the structure is being displayed.

Another method is to use the Drag and Drop Window. Using this window, you can drag and drop a document onto the Drag and Drop Window and the results will appear in Notepad (by default). You can then print the document from Notepad. To do this, make sure that the Drag and Drop Window is visible and that Use Validator on Dropped Files is checked. Then simply drag and drop the document that you want to validate onto the window.

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Why does HTML Validator's results differ from W3C's validator results?

W3C's main validation engine is a DTD based "real" validator while CSS HTML Validator's engine is more like real-world browsers and uses a custom designed HTML, XHTML, and CSS syntax checking engine. Because of the two different types of validation and parsing engines, the results of HTML Validator's engine and W3C's engine may be significantly different.

CSS HTML Validator's own validator engine is designed to be extremely powerful and to find many issues that other DTD based "real" validators and other syntax checkers cannot find. This is because DTD based validators are limited in the problems they can find due to technical constraints on what can be checked. Additionally, to save you time, CSS HTML Validator ignores many issues that are unlikely to cause problems so that you can concentrate on the more important problems.

However, if you still want results that are more similar to the W3C validator for pre-HTML5 documents, then you can use the included DTD based validator. You could also try the 'Standards compliant check' validation mode that more strictly checks based on the standards.

Read more about this issue in the answer to Does HTML Validator have a DTD ("real") validator?. You can also read why CSS HTML Validator is better.

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How do I check dynamic sites like PHP and ASP sites?

CSS HTML Validator is not designed to check raw/unprocessed ASP and PHP files (though it may still be useful in some cases, depending upon the structure of the document). We recommend that instead of checking the raw documents, that the output of the dynamic pages be checked instead.

To check the output of dynamic scripts, simply use the integrated web browser to browse your site's dynamic pages while at the same time displaying and checking the output. If any problems are found, then you can correct the script and then reload the page. HTML Validator can then automatically recheck the document.

You can also use the Batch Wizard (only in the Pro+ and Enterprise editions) to crawl your site and produce an HTML or XML report with the results.

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How do I check frames?

Validate the document containing the <frameset> tag and then go to the Links tab in the Results Window. Right-click to bring up the context menu on the link containing the HTML source of the frame you want to check and choose Open Link in Editor (or you may want to choose Open Link in Browser).

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Configuring the Validator

How do I validate more strictly to the standards?

If you want stricter standards-compliant syntax checking that generates errors for detected non-standard HTML and CSS, and adheres more strictly to the given document type (i.e. HTML4 vs HTML5), then try doing a 'Standards-compliant check' with Validate > Standards-compliant check.

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How do I configure HTML Validator to validate a new tag?

Please see the CSS HTML Validator Configuration Page.

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How do I configure HTML Validator to accept only certain strings for attribute values?

CSS HTML Validator Pro and above can do this using the onAttributeID_(id)() TNPL event function. For example, if you want to check the value of the class attribute which has an ID of 124 in the included configuration file, then you can create a user function named onAttributeID_124() and check the value in that function. Visit the onAttributeID_(id)() help topic for more information.

TNPL functions (also known as user functions) are functions that you can put into a text file which is then specified as a user function file in the Validator Engine Options.

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Can I make HTML Validator more strict/picky?

Try to check/uncheck these validator engine options for a stricter/pickier validation:

You can also use the 'Standards-compliant check' validation mode when validating. If desired, 'Standards-compliant check' can be specified as the default validation mode in the Validation > Set Default Validation Mode menu.

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How do I change a message type (like changing a warning message to an error message)?

In current versions you can easily change the type of a message by bringing up the context menu (usually done by right-clicking the mouse on the message). Then select Message Options > Change Message Type to and then select the new message type (or Default to use the default message type). Note that these options are not available for all messages. See the Message Types help topic for more information.

ADVANCED METHOD (Pro+ Edition): Use the onMessageAdding() TNPL function to alter validator messages (including message types).

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How do I export all the tag name programs to a text file?

In the Pro and Enterprise editions, TNPL programs and functions (also called tag name programs) can be exported to an XML file, edited, and imported back. Visit the Programs Editor online help topic for more information (see the section in that topic regarding exporting and importing the programs to/from an XML file).

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How do I switch between different sets of validation options?

You can use the import/export options in the Validator Engine Options to load and save different sets of validator options to and from files. This also makes it easier to share the validator options/settings with other users (just share the export file).

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Batch Processing/Validating

Can I generate a single report for multiple documents?

Using the Batch Wizard (only in the Pro and Enterprise editions), you can specify multiple documents to validate. The wizard will then create a single validation report for all of the documents. The report created by the wizard is written in standard HTML and can be viewed with any standard browser such as Chrome, Edge, or Firefox.

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Is there a way to batch process files?

You can drag and drop multiple files onto the Drag and Drop Window which is viewable by choosing Drag and Drop > View Drag and Drop Window. It is easy to do this by using Windows Explorer or the Find Files command to display the files, sorting the files by file type, and then dragging and dropping them onto the Drag and Drop Window.

Another way to batch process is to run cmdlineprocessor.exe on the command line with the name of the file to validate. You can run cmdlineprocessor.exe one time for each file, so you can make a batch program (*.bat) this way. The "-f" command can also be used for more efficient operation (see the documentation about Command Line Arguments for more information about the "-f" command).

Yet another way to batch process files is to use the Batch Wizard that is included with professional editions. This is considered to be the best and easiest way to batch process files. For more information, see the documentation about the Batch Wizard. Note that the Home/Standard and Lite editions do not include the Batch Wizard.

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How do I validate my website by giving HTML Validator one URL, file, or folder?

  1. Open the Batch Wizard (only in the Pro and Enterprise editions) by running CSS HTML Validator and then choosing Tools > Batch Wizard or pressing F2.
  2. Press Ctrl+N to create a new target list.
  3. Add a target that specifies the root page of your website. This can be a local file or a URL. To add a local file target, press Ctrl+F. To add a URL, press Ctrl+U. For example, if your site is at "http://www.mydomain.com/mysite/" then press Ctrl+U to add the URL "http://www.mydomain.com/mysite/" to the target list. You can also specify a folder where your website files are located by adding a folder target (Ctrl+D).
  4. Select the target that you just added and press F5 to view the target properties.
  5. Go to the Follow Links tab and check the follow links checkbox. Click OK.
  6. Press F4 to go to the Batch Wizard Options and select the "Validator" tool. Click OK.
  7. Press the Process List button (or press F6) to start the validation and process the target list.

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How do I exclude certain folders from being processed?

Entire folders can be excluded by entering the folder names in the "Do not process targets beginning with these strings" option in the Target List Options tab of the Batch Wizard. For example, add something like http://www.domain.com/donotgohere/ or C:\webfiles\donotgohere\. Separate multiple folders with semicolons.

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Link Checking

How do I check the links on my website using the link check tool?

  1. Load HTML Validator and press F2 to go to the Batch Wizard.
  2. Press Ctrl+N to create a new target list.
  3. Add a target that specifies the root page of your website. This can be a local file or a URL. To add a local file target, press Ctrl+F. To add a URL, press Ctrl+U. For example, if your site is at "http://www.mydomain.com/mysite/" then press Ctrl+U to add the URL "http://www.mydomain.com/mysite/" to the target list.
  4. Select the target that you just added and press F5 to view the properties.
  5. Go to the Follow Links tab and check the follow links checkbox. Click OK.
  6. Press F4 to go to the Batch Wizard Options and select the "Link check" tool. Click OK.
  7. Press F6 to start the link check.

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Features

Does HTML Validator support XHTML?

Yes. CSS HTML Validator will automatically set the below options in the Validator Engine Options if an XHTML document is detected.

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Does HTML Validator have a DTD ("real") validator?

CSS HTML Validator Std/Pro v8.0 and above include a DTD validator which can be used if turned on (it is turned off by default). However, CSS HTML Validator's own engine does not use a "real" SGML and DTD based validator as defined in the strict technical meaning of "HTML validator". We do not believe that concentrating on DTD based validation is important because:

However, keep in mind that if you want to use DTD validation for HTML4 and older documents, then the option is there in CSS HTML Validator Std/Pro v8.0 and above. The DTD based validator messages can be generated alone or can be combined with CSS HTML Validator's own messages if desired.

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Does HTML Validator fix my HTML?

Yes! The Home/Standard and higher editions include the Pretty Print/Fix/HTML Tidy Tool which uses HTML Tidy to automatically format ("pretty print") and fix HTML and XHTML. This tool can automatically fix some, but not all problems. Sometimes it is best to leave corrections up to the author to decide if to fix it, what to fix, when to fix it, and how to fix it. Programs that do "auto-fix" HTML may cause other problems or "fix" things in ways that the author doesn't want. However, depending on the specific document, the HTML Tidy Tool may be very helpful in fixing HTML problems. The Lite edition does not include the HTML Tidy Tool and therefore cannot automatically format and fix HTML.

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Miscellaneous Issues

How do I change the program associated with editing an HTML document? I don't want CSS HTML Validator associated with this anymore.

Go to Windows Explorer (start it if needed), choose View|Folder Options, and click the File Types tab. Note: The path to this dialog box may be different on your system; the above describes how to get to the needed dialog box on an NT 4.0 system with IE 4.0 installed, so your system may be different. When you are at the dialog box used to edit registered file types, 1) select "HTML Document" from the Registered file types list, 2) press the Edit button, 3) click on Edit in the Actions list and then 4) press the Remove or Edit button, depending on what you want to do. If you press the Edit button, you will need to assign the action to another program of your choosing.

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Will HTML Validator run on a Mac or Unix/Linux?

There is a new Linux and Mac command line port of CSS HTML Validator v23, called htmlval! See htmlval for Linux and htmlval for Mac for more information.

If you use Linux or a Mac and want to run the Windows GUI version of CSS HTML Validator then visit Run CSS HTML Validator on a Mac or Linux.

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Will HTML Validator run on the legacy operating systems Windows 7, 8, 8.1?

More recent versions up to (but not including) CSS HTML Validator 2023/v23 will officially run on Windows 7/8/8.1 and above.

CSS HTML Validator 2019/v19, 2020/v20, 2021/v21, and 2022/v22 require Windows 7 or above (64-bit only).

CSS HTML Validator 2023/v23 officially requires Windows 10/11 or above (64-bit only) and drops support for Windows 7/8/8.1, but is expected to run unofficially on Windows 7/8/8.1 without significant issues. Official support was dropped because Microsoft no longer supports these legacy operating systems in 2023.

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Will HTML Validator run on the legacy operating systems Windows 9x, XP, or Vista?

CSE HTML Validator v8.0 to v17.0 will run on Windows XP, Vista, Windows 7/8/8.1/10/11, and above, but these versions of CSE HTML Validator are now considered obsolete.

Note that official support for Windows XP was dropped in v15, however v15, v16, and v17 may still run on Windows XP if the latest service pack (SP3) is installed (but why are you still using Windows XP which was released over 20 years ago?).

CSS HTML Validator 2018/v18 requires Windows 7 or above (32-bit or 64-bit). Support for Windows Vista was dropped in 2018/v18.

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Do I need to be an HTML expert to use CSS HTML Validator?

Not at all! You only need to have a basic understanding of HTML or CSS or want to learn it. If you're a student, then CSS HTML Validator is an excellent program to use for learning and we even offer academic and student discounts.

CSS HTML Validator would not be for you if you don't have any knowledge of HTML or CSS and you do not want to learn.

If you do not have a basic knowledge of HTML and CSS but you want to learn HTML and CSS, then we recommending combining an online HTML tutorial or book with CSS HTML Validator. If at first you find yourself overwhelmed with all the messages that HTML Validator generates, then don't worry, you'll quickly catch on after a few days of use.

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How do I add words to the dictionary?

The easiest way to add words to the spell checker is to check a document in the editor using Tools > Spell Check (F7) and add any misspelled words to the dictionary when prompted.

You can also add words by going to Options > Editor Options and the Editor > Spell Checking page, then clicking on the More Spelling Options button, then going to the Language tab and adding words to one of the listed dictionaries by selecting the dictionary to edit and then pressing the Edit button (the selected dictionary must be editable or the Edit button will not be selectable).

If you have a large list of words that you want to add then you may want to download the dictionary utility and create your own dictionary.

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Legacy Issues (Applies to Obsolete Versions)

HTML Validator displays an "Insert disk" or "No Disk" message like "Please insert a disk into drive A:."

This is usually caused when the default selected folder in the Shell or Shell 2 tab of the Resource Window is on a removable drive and a disk is not in the drive. To solve this problem, either keep a disk in the default selected folder(s) or make the default selected folder a drive that does not use removable disks. You can do this by selecting the Shell tab in the Resource Window and selecting a different drive or folder (if the Resource Window is not visible then press Alt+F9). Do the same for the Shell 2 tab.

See also: HTML Validator freezes when trying to start

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