为何输入为空表单还是可以提交呢?<%@page contentType="text/html; charset=GBK"%>
<html>
<head>
<title>Login</title>
<script type="text/JavaScript" language="JavaScript">
function validate(){
f = document.reg_form;
if (f.username.value == "") {
alert("请输入用户名!");
f.username.foucs();
return false;
}else if (f.pwd.value == "") {
alert("请输入密码!");
f.pwd.foucs();
return false;
}
return true;
}
</script>
</head>
<body onload="document.reg_form.username.focus()">
<form action="wangnanloginservlet" name="reg_form" onsubmit="javascript:return validate()">
<p align="center">登录界面</p>
<p align="center"> 用户名:
<label>
<input type="text" name="username" size="12"/>
</label>
</p>
<p align="center"> 密
码:
<label>
<input type="password" name="pwd" size="12"/>
</label>
</p>
<p align="center">
<label>
<input type="submit" value="提交"/>
</label>
</p>
</form>
</body>
</html>
<html>
<head>
<title>Login</title>
<script type="text/JavaScript" language="JavaScript">
function validate(){
f = document.reg_form;
if (f.username.value == "") {
alert("请输入用户名!");
f.username.foucs();
return false;
}else if (f.pwd.value == "") {
alert("请输入密码!");
f.pwd.foucs();
return false;
}
return true;
}
</script>
</head>
<body onload="document.reg_form.username.focus()">
<form action="wangnanloginservlet" name="reg_form" onsubmit="javascript:return validate()">
<p align="center">登录界面</p>
<p align="center"> 用户名:
<label>
<input type="text" name="username" size="12"/>
</label>
</p>
<p align="center"> 密
码:
<label>
<input type="password" name="pwd" size="12"/>
</label>
</p>
<p align="center">
<label>
<input type="submit" value="提交"/>
</label>
</p>
</form>
</body>
</html>
<script language= "JavaScript">
function validate(){
if(document.reg_form.username.value =="") {
alert( "请输入用户名!");
document.reg_form.username.foucs();
return false;
}else if(document.reg_form.pwd.value =="") {
alert( "请输入密码!");
document.reg_form.pwd.foucs();
return false;
}
return true;
}
</script> 你这里主要的问题是不能用f = document.reg_form;这个来换,具体为什么我也不懂.还有就是你那type= "text/JavaScript "应该没有吧,不知道是你自己加的,还是真的有这样写法,见笑了.
应该是
(f.username.value == "") 和 }else if (f.pwd.value == "")