表单验证
<!DOCTYPE html>
<html lang="en">
<head>
<title></title>
<meta charset="UTF-8">
<link href="css/style.css"
rel="stylesheet">
</head>
<script language="Javascript">
function check()
{
if(form1.username.value=="" &&
form1.pwd.value=="" &&
form1.pwd1.value=="")
{
alert ("错误提示：请将所有资料填写完整！");
return false;
}
if(form1.username.value=="")
{
alert ("错误提示：用户名不能为空！");
return false;
}
if (form1.pwd.value=="")
{
alert ("错误提示：密码不能为空！");
return false;
}
if (form1.pwd1.value=="")
{
alert ("错误提示：账号不能为空！");
return false;
}
return true;
}
</script>
<body>
<form id="form1"
runat="server"
name="form1"
action="" onsubmit="">
<p align="center">
用户名：
<input type="text"
name="username" />
<p align="center">
密码：<input type="password"
name="pwd" />
<p align="center">
账号：<input type="password"
name="pwd1" />
<input type="submit"
value="登录"
onclick="return check()">
</form>
</body>
</html>