把网页中图片的Alt提示去掉的实现方法

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<img src="http://www.7gz.cn/images/logo.gif" alt="七歌站长站1号站">
<img src="http://www.7gz.cn/images/logo.gif" alt="七歌站长站2号站">
<img src="http://www.7gz.cn/images/logo.gif" alt="七歌站长站3号站">
<div style="visibility:hidden;border:0px solid #000000;background-color:#333333;font-size:12px;color:#6699cc;position:absolute;" id=altlayer></div>
<script>
document.body.onmousemove=quickalt;
function quickalt() {
if (event.srcElement.hint)event.srcElement.alt=event.srcElement.hint;
if(event.srcElement.alt && event.srcElement.alt!='') {
event.srcElement.hint=event.srcElement.alt;
altlayer.style.visibility='visible';
altlayer.style.left=event.x-1;
altlayer.style.top=event.y+16;
altlayer.innerHTML=event.srcElement.hint
event.srcElement.alt="";
}
else altlayer.style.visibility='hidden';}
</script>