function addEvent(o,t,fn){
	if( o.attachEvent ){
       		o['e'+t+fn] = fn;
	        o[t+fn] = function(){o['e'+t+fn](window.event);};
	        o.attachEvent('on'+t, o[t+fn]);
	}else{
       		o.addEventListener(t,fn,false);
	}
}

function getElementsByClassName( cls ){
	var root = document.getElementsByTagName( "body" )[0];
	var tags = root.getElementsByTagName( "*" );
	var ret = [];
	for( tag in tags ){
		if( tags[ tag ] && tags[ tag ].className && tags[ tag ].className.indexOf( cls ) >= 0 ){
			ret.push( tags[ tag ] );
		}
	}
	return ret;
}