<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="jquery-3.1.1.js"></script>
<script type="text/javascript">
$(function () {
var m1 = true;
var m2 = true;
if ($(".aa").val() =="") {
m1 = false;
}
if ($(".bb").val() =="") {
m2 = false;
}
$("#submit").click(function(){
if (m1 && m2) {
$('form').submit();
} else {
alert("用户名或者密码不能为空");
return false;
}
});
});
// $(function(){
// $("#submit").click(function(){
// alert("用户名不能为空");
// });
// });
</script>
</head>
<body>
<form action="http://www.w3cschool.cn/jquery/jquery-hide-show.html" method="post">
<table align="center">
<tr>
<td>请输入用户名：</td>
<td><input type="text" NAME="username" class="aa"></td>
</tr>
<tr>
<td>请输入密码：</td>
<td><input type="password" NAME="pwd" class="bb"></td>
</tr>
<tr>
<td colspan="2"><input type="submit" id="submit" name="submit" value="提 交"></td>
</tr>
</table>
</form>
</body>
</html>
