Butter CSS Loader

CSS Loader

var scriptElement,
            interval;

        checkFn = checkFn || function(){
          return !!scriptElement;
        };

        function runCheckFn() {
          interval = setInterval(function(){
            if( checkFn() ){
              clearInterval( interval );
              if( callback ){
                callback();
              }
            }
          }, CSS_POLL_INTERVAL );
        }

        url = fixUrl( url );

        if( !checkFn() ){
          scriptElement = document.createElement( "link" );
          scriptElement.rel = "stylesheet";
          scriptElement.onload = runCheckFn;
          scriptElement.href = url;
          document.head.appendChild( scriptElement );
        }
        else if( callback ){
          callback();
        }