<span style="font-family: Arial, Helvetica, sans-serif;">利用JS可以对用户登录时输入的信息进行初步判断,如有不符合格式的情况给予相应的提示。</span>
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<span style="font-family: Arial, Helvetica, sans-serif;">以下是代码示例 ,判断条件为用户名不能为空,密码必能少于三位</span>
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<span style="font-family: Arial, Helvetica, sans-serif;"><html xmlns="http://www.w3.org/1999/xhtml"></span>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>JS示例</title>
<style type="text/css">
table{
margin:0 auto;
}
</style>
<script type="text/javascript">
function validateFrom(){
//alert("Hello World!");
var nameText=document.getElementById("name").value;
var pwd=document.getElementById("pwd").value;
if(nameText==""||nameText.length==0){
alert("用户名不能为空!");
return false;
}else if(pwd.length<3){
alert("密码太短或为空!");
return false;
}
return true;
}
</script>
</head>
<body>
<form action="test-1.html" method="post" onsubmit="return validateFrom()">
<table>
<tr>
<td>用户名:</td>
<td><input type="text" id="name" name="name"/></td>
</tr>
<tr>
<td>密码:</td>
<td><input type="password" id="pwd" name="pwd"/></td>
</tr>
<tr>
<td><input type="submit" value="提交"/></td>
<td><input type="reset" value="重置"/></td>
</tr>
</table>
</form>
</body>
</html>