Detect feature support for CSS3 transitions.

transitions-supported.js

// warning: pseudo-code
var TRANSITIONS_SUPPORTED = false;
(function() {
    var div = document.createElement('div');
    div.innerHTML = '<div style="transition:color 1s linear;-ms-transition:color 1s linear;-o-transition:color 1s linear;-webkit-transition:color 1s linear;-moz-transition:color 1s linear;"></div>';
    var prefixes = ['', '-webkit-', '-moz-', '-o-', '-ms-'];
    for (var i=0; i<prefixes.length; i++) {
      if (prefixes[i] + 'transition' in div.firstChild.style) {
        TRANSITIONS_SUPPORTED = true;
        break;
      }
    }
})();