                        課程
                    
                        /前端開發
                        
                            /JavaScript
                        
                        /JS動畫效果

只能實現單獨的動畫效果，鏈式動畫不能夠執行。

<!DOCTYPE?html>
<html>
	<head>
		<meta?charset="UTF-8">
		<title>完美動畫</title>
		<style?type="text/css">
			*{
				margin:?0;
				padding:?0;
			}
			#li1{
				width:?400px;
				height:?100px;
				background:?green;
				border:?2px?solid?blue;
				opacity:?0.3;				
			}
		</style>
		<script?src="js/move.js"></script>
		<script?type="text/javascript">
			window.onload=function(){
				var?aLi=document.getElementById('li1');
				aLi.timmer=null;
				aLi.onmouseover=function(){
					startMove(aLi,'height',200,function(){
						alert(1);
					});
				}
			}
		</script>
	</head>
	<body>
		<ul>
			<li?id="li1"></li>
		</ul>
	</body>
</html>

function?getStyle(obj,?atttr)?{
	if(obj.currentStyle)?{
		return?obj.currentStyle[atttr];
	}?else?{
		return?getComputedStyle(obj,?false)[atttr];
	}
}

function?startMove(obj,?attr,?iTarget,?fn)?{
	clearInterval(obj.timmer);
	obj.timmer?=?setInterval(function()?{
		var?icur?=?0;
		if(attr?==?'opacity')?{
			icur?=?Math.round(parseFloat(getStyle(obj,?attr))?*?100);
		}?else?{
			icur?=?parseInt(getStyle(obj,?attr));
		}
		var?speed?=?(iTarget?-?icur)?/?8;
		speed?=?speed?>?0???Math.ceil(speed)?:?Math.floor(speed);
		if(iTarget?==?speed)?{
			clearInterval(obj.timmer);
			if(fn)?{
				fn();
			}
		}?else?{
			if(attr?==?'opacity')?{
				obj.style.opacity?=?(icur?+?speed)?/?100;
			}?else?{
				obj.style[attr]?=?(icur?+?speed)?+?'px';
			}
		}
	},?30);
}

鼠標移動到Li上面以后，寬度能夠順利的改變，換成透明度，高度等也能夠執行。但是不能夠執行鏈式動畫，比如那個alert(1)。大神幫忙解答一下。。。。