这个是那里错了~？
<html ><head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
<script language="javascript">
function calculate(form)
{
form.result.value = eval(form.ente.value);
}
function getExpression(form)
{
form.ente.blur();
form.ente.value = prompt("Please enter a JavaScript mathematical expression","");
calculate(form);
}
</script>
</head>
<body>
<form method="post" >
Enter a JavaScript mathematical expression:
<input type=text name="ente" value="" onfocus ="getExpression(this.form);" />
<br>
The result of this expression is:
<input type=text name="result" value="" onfocus ="this.blur();" />
</form>
</body>
</html>
