<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>js登录界面演示</title>
</head>
<body>
<center>
<form name="form1" aciton="" method="get">
<label>用户名:</label><input name="username" type="text" maxlength="20"/>
<label>密码:</label><input name="pwd" type="password" maxlength="20" />
<input name="Button" type="button" value="登录" onclick="check()"/>
<input name="Submit" type="reset" value="重置" />
</form>
</center>
</body>
<script>
function check()
{
if(form1.username.value=="") //判断用户名是否为空
{
alert("请输入用户名!");
form1.username.focus();
return;
}
else if(form1.pwd.value==""){ //验证密码是否为空
alert("请输入密码!");
form1.pwd.focus();
return;
}
else{
form1.submit(); //提交表单
}
}
</script>
</html>