JQuery Duplicate Email Validation

Question

I have just started studying programming and I've been stuck for hours in this problem. I have a sign up form which asks for email and it should check the mysql database if the email is already registered. I am currently trying to use the remote method from the Jquery validator plugin but I can't seem to make it work.

emailcheck.php

<?php
include_once 'dbconnect.php';
$email = $_POST['CusEadd'];
$query = "SELECT CusEadd FROM customer WHERE CusEadd='$email'";
$result = mysql_query($query);
$count = mysql_num_rows($result);

if($count>0){
    echo json_encode(FALSE);
}
else {
    echo json_encode(TRUE);
}

?>

form-validation.js

CusEadd: {  
            required:true,
            email:true,
            remote:"emailcheck.php"
        }

If you're using the jQuery validate plugin, I believe it makes a GET request by default, you'd have to specify POST if that's what you want — adeneo
– adeneo, Commented Oct 25, 2016 at 19:31
Especially if you're just starting to learn programming please don't use PHP's mysql_* functions. They were deprecated in PHP 5.5, which is so old that it no longer receives security updates, and completely removed in PHP 7. Instead, use PDO or mysqli_*. — Chris
– Chris, Commented Oct 25, 2016 at 19:34
Yeah. I would definitely stop using mysql and learn how to use PDO. thanks guys! — aeonxs11
– aeonxs11, Commented Oct 25, 2016 at 19:44

adeneo · Accepted Answer · 2016-10-25 19:35:00Z

1

The documentation for jQuery Validate states that

The serverside resource is called via jQuery.ajax (XMLHttpRequest) and gets a key/value pair corresponding to the name of the validated element and its value as a GET parameter.

The serverside response must be a JSON string that must be "true" for valid elements, and can be "false", undefined, or null for invalid elements

You're checking for $_POST['CusEadd'], and assuming you have an element with that name, you still have to specify POST as a method

CusEadd: {  
    required:true,
    email:true,
    remote: {
        url  : "emailcheck.php",
        type : "POST"
    }
}

Also, you want to return the string "true", not PHP booleans, which usually converts to numbers

if($count>0){
    echo json_encode("false");
}
else {
    echo json_encode("true");
}

And do not use mysql_* in production code, your code is open to SQL attacks by simply passing something like 'OR 1=1 to the POST variable

answered Oct 25, 2016 at 19:35

adeneo

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1 Comment

aeonxs11 Over a year ago

Thank you!! Thank you very much! You are a real life saver. And also I'm gonna remove the mysql and use mysqli instead. thank you again!!

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