失去焦点时，调用方法：
<html>
<head>
<script type="text/javascript">
function upperCase()
{
var x=document.getElementById("fname").value
document.getElementById("fname").value=x.toUpperCase()
}
</script>
</head>
<body>
Enter your name: <input type="text" id="fname" onblur="upperCase()"><br />
Enter your age: <input type="text" id="age" onblur="alert(this.id)">
</body>
</html>