Vendor Prefixes

The number of CSS properties is fairly large, and it's likely that you won't use all of them.

The number of CSS properties is also growing! Experimental and nonstandard properties are constantly being added to browsers, but using them will require a special prefix until the properties are standardized.

In order to use experimental features, the MDN documentation for a property will usually be associated with vendor prefixes. Here's an example with CSS transitions.

.button {
  -webkit-transition: background-color 1s ease-out 1s;
  -moz-transition: background-color 1s ease-out 1s;
  -o-transition: background-color 1s ease-out 1s;
  transition: background-color 1s ease-out 1s;
}

This example has three vendor prefixes, for Webkit browsers (Safari, Chrome), Mozilla (Firefox), and Opera. There are additional prefixes for Internet Explorer and Edge as well.

Note that if a browser finds a matching prefix, it will ignore the other prefixes. Therefore, using properties with vendor prefixes will require us to define the standard syntax last.