我按书上写的,什么不能正确执行?请大家看一下,我是刚学的?
按书上写的,但提示是21行却少对象?不懂,,onChange事件不用吗?
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>无标题文档</title>
</head>
<body>
<script language="JavaScript">
function checkData()
{
if (document.form1.three.value.length==3)
alert("OK!有效!");
else
{
alert("请输入三个字符,"+document.form1.three.value+"无效!");
returm false
}
}
</script>
<form name="form1">
<center>
请输入字符:<input type="text"name="three"onChange="checkData()">
</center>
</form>
</body>
</html>
