javascript简单判断表单(用户名密码是否为空,密码长度)
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>表单简单判断</title>
</head>
<body>
<form action="" method="post" name="form1" target="_blank" id="form1"
onSubmit="return check_login()">
<table width="30%" height="144" border="0" align="center">
<tr>
<td width="19%">用户名:</td>
<td width="81%"><label for="username"></label>
<input name="username" type="text" id="username" size="25" maxlength="30" /></td>
</tr>
<tr>
<td>密码:</td>
<td><label for="password"></label>
<input name="password" type="password" id="password" size="25" maxlength="30" /></td>
</tr>
<tr>
<td> </td>
<td><input type="submit" name="button" id="button" value="提交" />
<input type="reset" name="button2" id="button2" value="重置" /></td>
</tr>
<tr>
<td> </td>
<td> </td>
</tr>
</table>
</form>
</body>
<script language="javascript">
function check_login()
{
if(document.form1.username.value==""")/*document.表单名.文本域名.value=="""*/
{
alert("请检查用户名是否为空!");
return false;
}
if(document.form1.password.value=="""){
alert("请检查您的密码是否为空!");
return false
}
if(document.form1.password.value.length<6){
alert("您的密码长度小于6!");
return false
}
}
</script>
</html>
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