function JSLoaderEnvironment(){

  this.loadJavaScript=function (id,url){
      if(!document.getElementById(id)){
            var oHead = document.getElementsByTagName('head')[0];
            var oScript = document.createElement( "script" );
            oScript.type = "text/javascript";
            oScript.src = url;
            oHead.appendChild( oScript );
      }
  };
};


var JSLoader = new JSLoaderEnvironment();