Detect CSS3 Support in Browsers with JavaScript

CSS3 Support

var supports = (function() {  
   var div = document.createElement('div'),  
      vendors = 'Khtml Ms O Moz Webkit'.split(' '),  
      len = vendors.length;  
  
   return function(prop) {  
      if ( prop in div.style ) return true;  
  
      prop = prop.replace(/^[a-z]/, function(val) {  
         return val.toUpperCase();  
      });  
  
      while(len--) {  
         if ( vendors[len] + prop in div.style ) {  
            // browser supports box-shadow. Do what you need.  
            // Or use a bang (!) to test if the browser doesn't.  
            return true;  
         }   
      }  
      return false;  
   };  
})();  
  
if ( supports('textShadow') ) { 
   document.documentElement.className += ' textShadow';  
}