?? ? ?? ?? ??
?? ? ?? ?? ??
1. onsubmit ???? ?? ?? ??? ?????(?? ????? ???)
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>php.cn</title>
<script type="text/javascript">
function checkForm()
{
//判斷用戶(hù)名是否為空
if(document.form1.username.value=="")
{
window.alert("用戶(hù)名不能為空！");
return false;
}else
{
window.alert("驗(yàn)證通過(guò)！");
return true;
}
}
</script>
</head>
<body>
<form name="form1" method="post" action="login.php" onsubmit="return checkForm()">
用戶(hù)名：<input type="text" name="username" />
密碼：<input type="password" name="userpwd" />
<input type="submit" value="提交表單" />
</form>
</body>
</html> 2 . ?? ?? ? ??? ???? ?? onclick ???? ??? ?? ??
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>php.cn</title>
<script type="text/javascript">
function checkForm()
{
//判斷用戶(hù)名是否為空
if(document.form1.username.value=="")
{
window.alert("用戶(hù)名不能為空！");
}else
{
window.alert("驗(yàn)證通過(guò)！");
}
}
</script>
</head>
<body>
<form name="form1" method="post" action="login.php">
用戶(hù)名：<input type="text" name="username" />
密碼：<input type="password" name="userpwd" />
<input type="submit" value="提交表單" onclick="checkForm()" />
</form>
</body>
</html>3. ?? ?? ? ??? ???? ?? submit() ???? ??? ?? ?? ??
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>php.cn</title>
<script type="text/javascript">
function checkForm()
{
if(document.form1.username.value.length == 0)
{
//如果用戶(hù)名為空
window.alert("用戶(hù)名不能為空！");
}else if(document.form1.username.value.length<5 || document.form1.username.value.length>20)
{
//如果用戶(hù)名長(zhǎng)度小于5或大于20
window.alert("用戶(hù)名只能介于5-20個(gè)字符！");
}else if(checkOtherChar(document.form1.username.value))
{
//如果用戶(hù)名含有特殊符號(hào)
window.alert("用戶(hù)名中含有特殊符號(hào)！");
}else
{
//如果驗(yàn)證通過(guò)，提交表單
window.alert("驗(yàn)證通過(guò)！");
//表單提交方法
document.form1.submit();
}
}
function checkOtherChar(str)
{
//定義一個(gè)特殊符號(hào)的數(shù)組
var arr = ["*","&","<",">","$","\","/"];
//循環(huán)比較：數(shù)組中的每一個(gè)字符，與用戶(hù)名每一個(gè)字符進(jìn)行比對(duì)
for(var i=0;i<arr.length;i++)
{
for(var j=0;j<str.length;j++)
{
if(arr[i]==str.charAt(j))
{
return true;
}
}
}
//如果沒(méi)找到
return false;
}
</script>
</head>
<body>
<form name="form1" method="post" action="login.php">
用戶(hù)名：<input type="text" name="username" />
密碼：<input type="password" name="userpwd" />
<input type="button" value="提交按鈕" onclick="checkForm()" />
</form>
</body>
</html>
