JS-运动基础（一）续

时间：2015-03-07 13:52:46 阅读：122 评论：0 收藏：0 [点我收藏+]

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2.淡入淡出的图片

用变量存储透明度

<title>无标题文档</title>
<style>
#div1{width:293px; height:220px; background:url(‘images/05.jpg‘);filter:alpha(opacity:30);opacity:0.3;}
</style>
<script>
window.onload=function ()
{
    var oDiv=document.getElementById(‘div1‘);
    oDiv.onmouseover=function ()
    {
        startMove(100);
    }
    oDiv.onmouseout=function ()
    {
        startMove(30);
    }
}
var alpha=30;
var timer=null;
    
function startMove(iTarget)
{
    var oDiv=document.getElementById(‘div1‘);
        
    clearInterval(timer);
    timer=setInterval(function (){
                        var speed=0;
                        if(alpha<iTarget)
                        {
                            speed=10;
                        }
                        else
                        {
                            speed=-10;
                        }
                            
                        if(alpha==iTarget)
                        {
                            clearInterval(timer);
                        }
                        else
                        {
                            alpha+=speed;
                                
                            oDiv.style.filter=‘alpha(opacity:‘+alpha+‘)‘;
                            oDiv.style.opacity=alpha/100;
                        }
                    },30);
}
</script>
</head>

<body>
<div id="div1"></div>
</body>