Fastest way to get a browser prefix. http://jsperf.com/fastest-prefix-check/2

fastest_prefix.js

function testForComputedMatches() {
  var prefixes = 'webkit moz ms o'.split(' '), lt = prefixes.length, prefix = '', computed;

  while (lt--) {
    computed = window.getComputedStyle && window.getComputedStyle(document.body).getPropertyValue("-"+prefixes[lt]+"-transform");
    if (!!computed) {
      prefix = prefixes[lt];
      break;
    }
  }
  return prefix;
}