CSS Browser extensions

When you use a browser extension such as -moz-property:value; -webkit-property:value… I have read that the browser manufacturers will drop the extension version of a style once they adopt the official version. Does this mean that when they drop the extension you have to go in and edit all the websites you included them in to avoid the style sheets to stop working?
Also, have Microsoft, Firefox and Opera started to support the -webkit extension? In other words do you have to include the -moz, -o, -ms - or can you just use -webkit to cover all of them?

“Vendor” prefixes as they are known are there so you can use some newer CSS rules in that browser until the browser version actually implements the real thing.

So for newer CSS rules it’s always a good idea to use the default CSS rule and apply vendor prefixes as required. If the users browser version is old it may use the vendor prefixed style, or if it’s more up to date it will use the normal rule.

Here’s an example:

.myclass {
-moz-border-radius: 12px; // for older firefox browser versions
-webkit-border-radius: 12px; // for older webkit browser versions
border-radius: 12px; // normal/default used by new browsers
}

So if, say, Firefox drops -moz-border-radius at some point it will simply ignore that rule and use the default border-radius instead.