The "opacity" CSS Property

This property sets the opacity of an element as a whole, including its contents, rather than applying it to each descendant individually.

Values for "opacity"

CSS Level	Value
CSS Color Level 4	"<opacity-value>", where <opacity-value> = "<number> | <percentage>" (mapped/clamped to the range [0,1])

Notes

• 0 is fully transparent and 1 is fully opaque (solid). Any values outside the range 0.0 (fully transparent) to 1.0 (fully opaque) will be clamped to this range.

Recommended Links

• CanIUse.com: Search "opacity" (browser compatibility information)
• CanIEmail.com: Search "opacity" (email client compatibility information)
• CSS3: opacity property
• MDN: opacity property
• Quackit: opacity property

Search Engine Links (for more information)

• Bing "CSS opacity property"
• Google "CSS opacity property"