我想使用javascript验证我的表单。在表单提交之前，我希望服务器在字段输入下方显示错误（如果有的话）。我可以在这段代码中使用外部javascript文件吗？ / p>
这是我的代码：
<!DOCTYPE HTML>
<html>
<head>
<style>
.error {color: #FF0000;}
.label_text {
float: left;
width: 44%;
text-align:right;
font-weight:bold;
color:purple;
}
.register1{
text-align:center;}
.header_tag{text-align:center;
font-weight:bold;
color:green;}
.header_tag1{ margin:10px;
float:left;
text-align:center;
font-weight:bold;
color:green}
.register_section{border:1px solid black;
text-align:center;
padding:20px;
margin-left:30%;
margin-right:30%;
float:none;
height:350px;
}
.input{ text-align:left;
float:left;
border:2px solid black;
}
.gender{float:left;}
.register{ float:left;
text-align:center;
color:green;
font-weight:bold;
padding:10px;
margin-left:36%;}
</style>
</head>
<body>
<?php
// define variables and set to empty values
$nameErr = $passwordErr = $password2Err = $emailErr = $genderErr = "";
$name = $password = $confirmpassword = $email = $gender = $description = "";
$result="";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
$username = "";
$password = "";
$hostname = "";
//connection to the database
$dbhandle = mysql_connect($hostname, $username, $password)
or die("Unable to connect to MySQL");
echo "Connected to MySQL<br>";
//select a database to work with
$selected = mysql_select_db("test",$dbhandle)
or die("Could not select test");
if (empty($_POST["name"])) {
$nameErr = "Name is required";
} else {
$name = test_input($_POST["name"]);
if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
$nameErr = "Only letters and white space allowed";
}
}
if (empty($_POST["password"])) {
$passwordErr = "Password is required";
} else {
$password = test_input($_POST["password"]);
}
if (empty($_POST["confirmpassword"])) {
$password2Err = "Confirm Password";
} else {
$password = test_input($_POST["confirmpassword"]);
}
if ($_POST['password']!= $_POST['confirmpassword'])
{
echo("Oops! Password did not match! Try again. ");
}
if (empty($_POST["email"])) {
$emailErr = "Email is required";
} else {
$email = test_input($_POST["email"]);
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
$emailErr = "Invalid email format";
}
}
if (empty($_POST["description"])) {
$comment = "";
} else {
$comment = test_input($_POST["description"]);
}
if (empty($_POST["gender"])) {
$genderErr = "Gender is required";
} else {
$gender = test_input($_POST["gender"]);
}
if (empty($genderErr))
{if (empty($emailErr)){
if (empty($password2Err)){
if (empty($passwordErr)){
if (empty($nameErr)){
$result=mysql_query("SELECT * FROM person WHERE username ='$name' AND password='$password'AND Email='$email'");
if (mysql_num_rows($result)==0 )
{ // IF no previous user is using this username.
$result1=mysql_query("INSERT INTO person(username,password,Email,Gender) VALUES ( '$name', '$password','$email','$gender')");
{ if($result1)
////If the Insert Query was successfull.
// Send an email
// Finish the page:
{
echo '<div class="success">Thank you for registering! A confirmation email has been sent to ' . $email . ' </div>';
}
else
{ // If it did not run OK.
echo '<div class="errormsgbox">You could not be registered due to a system error. We apologize for any inconvenience.</div>';
}
}
}
// The username is not available.
else
{ echo '<div class="errormsgbox" >That username has already been registered.</div>';
}
}
}
}
}
}
}
function test_input($data) {
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
return $data;
}
?>
<div class="register1">
<h2 class="header_tag">REGISTER HERE</h2>
<p><span class="error"></span></p>
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
<div class="register_section">
<div class="label_text">
Name:<span class="error">* </div>
<div class="input">
<input type="text" name="name"><br> </div>
<span class="error"><?php echo $nameErr;?></span>
<br><br>
<div class="label_text">
Password:<span class="error">* </div>
<div class="input">
<input type="text" name="password"><br> </div>
<span class="error"><?php echo $passwordErr;?></span>
<br><br>
<div class="label_text">
Confirm Password:<span class="error">* </div>
<div class="input">
<input type="text" name="confirmpassword"><br> </div>
<span class="error"><?php echo $password2Err;?></span>
<br><br>
<div class="label_text">
E-mail:<span class="error">* </div>
<div class="input">
<input type="text" name="email"><br></div>
<span class="error"><?php echo $emailErr;?></span>
<br><br>
<div class="label_text">
Description: </div>
<div class="input">
<textarea name="description" rows="5" cols="22"></textarea> </div>
<br><br>
<div class="label_text">
Gender:<span class="error">* </div>
<div class="gender">
<input type="radio" name="gender" value="female">Female
<input type="radio" name="gender" value="male">Male
</div>
<span class="error"><?php echo $genderErr;?></span>
<br><br><br>
<div class="register">
<input type="submit" name="submit" value="REGISTER">
<br>
<h3 class="header_tag1">"<a href="login_access.php">Back to Login</a>
</div>
</div>
</div>
</form>
</body>
</html>
答案 0 :(得分：1)
您要做的是正确地称为客户端验证。
最简单的方法是使用第三方库，例如FormValidation。
例如，要验证您的电子邮件字段，您可以执行以下操作：
<form method="post" id="register_user" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
...
<input type="text" name="email" data-fv-emailaddress="true" data-fv-emailaddress-message="The value is not a valid email address" />
...
</form>
<script>
$('#register_user').submit(function() {
$('#register_user').formValidation();
});
</script>
当然，您需要确保为jQuery，FormValidation和合适的内容框架（例如Bootstrap）包含必要的CSS和JS库。
为了记录，如果您只是在寻找基本的用户管理脚本，我强烈建议您避免重新发明轮子。获取现有脚本，例如UserFrosting，然后根据您的需要进行修改。