js 淡入淡出的图片

时间：2024-05-04 20:33:31
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head>

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

<title>js淡入淡出的图片</title>

<style>

#img{display:block;margin:0 auto; opacity:0.3; filter:alpha(opacity=30); width:200px; height:300px;}

</style>

<script>

window.onload=function(){

var oImg=document.getElementById('img');

var iTimer=0;

oImg.onmouseover=function(){

   startMove(this,100,10);

}

oImg.onmouseout=function(){

   startMove(this,30,-10);

}

function startMove(obj, iTarget, iSpeed) {

        clearInterval(iTimer);

        var iCur=0;

        iTimer = setInterval(function() {

            iCur=Math.round(css(obj,'opacity')*100);

            if (iCur == iTarget) {

                clearInterval(iTimer);

            } else {

                obj.style.opacity=(iCur+iSpeed)/100;

                obj.style.filter='alpha(opacity='+(iCur+iSpeed)+')';   //加括号防止转换成字符串

            }

        }, 30);

    }

function css(obj,attr){       //获取元素的css任何属性

  if(obj.currentStyle){

      return obj.currentStyle[attr];

   }else{

     return getComputedStyle(obj,false)[attr];

   }

}}

</script>

</head>

<body>

<img src='cat.jpg' id='img'/>

</body>

</html>

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