vendor_prefix.js

// How to determine if you need a vendor prefix to access a CSS property.
//
// License: http://github.com/stilist/ratafiacurrant/blob/master/License

var vendorPrefixes = ["", "-webkit-", "-moz-"];
var test = document.createElement("div");
// http://unscriptable.com/index.php/2009/05/01/a-better-javascript-memoizer/
var cssPrefix = (function () {
	var cache = {};
	return function (property, value) {
		if (null === value) {
			value = 1;
		}
		if (undefined === cache[property]) {
			for (var i = 0; i < vendorPrefixes.length; ++i) {
				var composedName = vendorPrefixes[i] + property;
				test.style.composedName = value;
				var cStyle = document.defaultView.getComputedStyle(test, null);
				if (null !== cStyle.getPropertyValue(composedName)) {
					cache[property] = vendorPrefixes[i];
					break;
				}
			}
		}
		return cache[property];
	};
})();

// "-webkit-"
alert(cssPrefix("column-count"));
// ""
alert(cssPrefix("border-width"));
// "" -- cache hit
alert(cssPrefix("border-width"));
// undefined
alert(cssPrefix("asdfasdf"));