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                        /JS動(dòng)畫(huà)效果

請(qǐng)問(wèn)這BUG是什么情況？

<!DOCTYPE?html>
<html>

	<head>
		<meta?charset="UTF-8">
		<title></title>
		<style?type="text/css">
			*?{
				margin:?0;
				padding:?0;
			}
			
			.lis?{
				height:?60px;
				width:?260px;
				background-color:?antiquewhite;
				border-radius:?60px;
				margin-top:?10px;
				line-height:?60px;
				text-align:?center;
				border:?5px?solid?cadetblue;
				opacity:?0.5;
				box-shadow:?5px?2px?10px?darkred;
			}
		</style>
	
		<script?type="text/javascript">
			function?getclsname(clsname,?parent)?{
				var?oparent?=?parent???document.getElementById(parent)?:?document,
					eles?=?[],
					elements?=?oparent.getElementsByTagName("*");
				for?(var?i?=?0,?l?=?elements.length;?i?<?l;?i++)?{
					if?(elements[i].className?==?clsname)?{
						eles.push(elements[i]);
					}
				}
				return?eles;
			}
/*			function?getstyle(obj,sty){
				if(obj.currentStyle){
					return?obj.currentStyle[sty];
				}else{
					return?getComputedStyle(obj,null)[sty];
				}
			}*/
			
			window.onload?=?function()?{
				var?lis?=?getclsname("lis",?"oul"),
					btn=document.getElementById("bt"),
					txt=document.getElementById("text"),
					speed?=?10,
					sty?=?null;
				btn.onclick=function(){
					sty=txt.value;
					document.title=sty;
				}
				for?(var?i?=?0,?l?=?lis.length;?i?<?l;?i++)?{
					this.timer=null;
					lis[i].onmouseover?=?function()?{
						lis_over(this,?speed,?0,?500,1,sty);
					}
					lis[i].onmouseleave?=?function()?{
						lis_over(this,?speed,?1,?260,0.5,sty);
					}
				}
			}

			function?lis_over(obj,?speed,?lg,?itg,op,sty)?{
				clearInterval(obj.timer);
				obj.timer?=?setInterval(function()?{
					var?wd=window.getComputedStyle(obj,null)[sty];
					if(sty=='opacity'){
						wd=Math.round(parseFloat(wd)*100);
					}else{
						wd=parseInt(wd);
					}
					if?(wd?==?itg||wd/100==op)?{
						clearInterval(obj.timer);
					}?else?{
						if(lg!=0){
							speed=-10;
						}
						if(sty=='opacity'){
							var?a?=?wd?+?speed;
							if(a<0||a==0){
								obj.style[sty]?=?op;
								clearInterval(obj.timer);
							}else{
								obj.style[sty]?=?a/100;
							}
						}else{
							if(wd>itg&&lg!=0){
								obj.style[sty]=itg+"px";
								clearInterval(obj.timer);
							}else?if(wd<itg&&lg==0){
								obj.style[sty]=itg+"px";
								clearInterval(obj.timer);
							}
							if(wd>800/2){
								if(lg==0){speed=sp+10;}
								else{speed=-sp-10;}
							}
							obj.style[sty]?=?wd?+?speed?+?"px";
						}
					}

				},?100)
			}

		</script>
	</head>

	<body>
		<div>
			<input?type="text"?id="text"?style="color:grey"?value="opacity"?onfocus="this.value=''"/>
			<input?type="button"?id="bt"?value="確定"?/>
		</div>
		<ul?id=oul>
			<li?class="lis">imooc</li>
			<li?class="lis"></li>
			<li?class="lis"></li>
			<li?class="lis"></li>
			<li?class="lis"></li>
			<li?class="lis"></li>
		</ul>
	</body>

</html>