鼠标划过，图片会变，离开又回复到初识状态
<!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>无标题文档</title>
<script>
function $(eid){
return document.getElementById(eid);
}
function over(){
var obj=$("myImg");
obj.src="../images/fruit.jpg";
}
function out(){
var obj=$("myImg");
obj.src="../images/grape.jpg";
}
</script>
</head>
<body>
<img id="myImg" src="../images/grape.jpg" onmouseover="over()" onmouseout="out()"/>
</body>
</html>
鼠标经过:调用onmouseover()方法、鼠标离开调用out()方法