CSS HTML Validator Quick Start Guide (for Printing)

NOTE: Please print this quick start guide.


  1. If you haven't already, download CSS HTML Validator from www.htmlvalidator.com.
  2. Run the setup program you downloaded and follow the setup instructions (the trial version is usually named CSS-HTML-Validator-Trial-Setup.exe).

Launching CSS HTML Validator and Validating Documents

  1. To launch CSS HTML Validator, press the Windows key and type "CSS". The program should appear as one of the options and you can select it to run it.
  2. To validate a local document, open the document using File > Open or the Ctrl+O shortcut key.
  3. To validate a URL, open the URL using File > Open from the Web or the Shift+Ctrl+O shortcut key.
  4. Press F6 to validate the current document. The validation results should appear in the Message Window.

Reviewing the Validation Messages

  1. After validating (like with F6), the validation messages appear in the Results Window.
  2. Click or double-click on a validator message to be taken to the location of the document that generated that message (if available).
  3. Some errors and warnings may be contained in other tabs. Review the messages in the various tabs (like Grouped, Accessibility, Styles).
  4. The Line tab will show the messages for the line that the cursor is on. For example, if you see that line 26 is highlighted and want to see the messages for that line, then select the Line tab and then place the cursor on line 26.
  5. Review the Links tab to see the links in the document and to check the links.
  6. When you click on a validator message, the full text of the message is displayed in the Message Window. If this window is not visible, then select View > Windows > Message.

Customizing the Validation Messages

  1. Right-click on the messages to bring up a context menu that allows you to disable the message or change its type (like from an error to a warning or from a warning to an error).
  2. Note that not all options may be available for all messages.
  3. These customization features allow you to customize the validation messages for your own needs, showing the messages that you want and not showing those that you don't want.

Helpful Tips

  1. Place the cursor on or near an HTML element or CSS property and press F1 to open a help page for it (we call this 'Dynamic Help').
  2. Find the matching start or end tag with Ctrl+M.
  3. Use the inserters to quickly insert HTML elements, CSS properties, and more (View > Toolbars > Inserters).

Explore More

Refer to the online help (accessible from the main support page) or offline help (accessible from Help > Help Contents or Ctrl+F1) for the following:

  1. Many configuration options, including adding your own custom messages and user functions.
  2. Validating entire websites or parts of them using the Batch Wizard (Pro+).
  3. Scheduling validations or link checks.
  4. Checking lists of links or email addresses.
  5. Syntax checking PHP code and linting JavaScript.