check username availability with jQuery

Question

I am using this function to check username availability when registering, and if the username exist, the submit button is disabled. I'm using a php script to check if the username exists in the database. The code works perfectly in my local server, but when hosted on a Godaddy server, I get the below error when I submit or when I try to navigate to another page:

After the empty response, I can't access my website for about a minute and then it's fine.

I tried a lot of things like calling jquery.js file before all other js files, but nothing works for me.

I am not very good with jQuery and javascript. Thank you for your suggestions.

ere is the script and the HTML form :

 function check_availability_username() { var min_chars = 4; var max_chars = 30; var re = /^\\w+$/; var characters_error1 = 'Minimum amount of chars is 4'; var characters_error2 = 'Maximum amount of chars is 30'; var characters_error3 = 'Chars can be only letters, numbers and underscores!'; var checking_html = 'Checking...'; var username = $('#username').val(); $.post("check_username.php", { username: username }, function(result) { if (result == 1) { if ($('#username').val().length < min_chars) { $('#username_availability_result').html(characters_error1); $('input[name=submit]').attr('disabled', true); } else if ($('#username').val().length > max_chars) { $('#username_availability_result').html(characters_error2); $('input[name=submit]').attr('disabled', true); } else if (!re.test($('#username').val())) { $('#username_availability_result').html(characters_error3); $('input[name=submit]').attr('disabled', true); } else { $('#username_availability_result').html(username + ' is Available'); $('input[name=submit]').attr('disabled', false); } } else { $('#username_availability_result').html(username + ' is not Available'); $('input[name=submit]').attr('disabled', true); } }); if (event.which == 13 || event.keyCode == 13) { $.post("check_username.php", { username: username }, function(result) { if (result == 0) { $('#username_availability_result').html(username + ' is not Available'); $('input[name=submit]').attr('disabled', true); } }); } $('#submit').click(function() { $.post("check_username.php", { username: username }, function(result) { if (result == 0) { $('#username_availability_result').html(username + ' is not Available'); $('input[name=submit]').attr('disabled', true); } }); }); } 

 <form id="login-id" action="suscribe-form.php" method="POST" onkeyup="return check_availability_username();"> <div class="form-group"> <label for="username">Username</label> <input type="text" class="form-control button-or-space" name="username" id="username" value="" minlength="4" maxlength="25" required pattern="\\w+"> <input type='hidden' id='check_username_availability' value='Check Availability'>&nbsp;<span id='username_availability_result' name='username_availability_result'></span> </div> <div class="form-group"> <label for="password1">Password</label> <input type="password" class="form-control button-or-space" name="password1" id="password1" value="" minlength="8" maxlength="60" required pattern="(?=.*\\d)(?=.*[az])(?=.*[AZ]).{8,}" onchange="form.password2.pattern = this.value;"> </div> <div class="form-group"> <label for="password2">Confirm password</label> <input type="password" class="form-control button-or-space" name="password2" value="" minlength="8" maxlength="60" required pattern="(?=.*\\d)(?=.*[az])(?=.*[AZ]).{8,}"> </div> <div class="form-group pull-right"> <input type="submit" name="submit" id="submit" value="Register" class="btn btn-success button-or-space"> </div> </form> 

And here is the php script :

<?php    

mysql_connect('localhost', 'root', '');
mysql_select_db('DB');

$username = mysql_real_escape_string($_POST['username']);

$result = mysql_query('select username from user where username = "'.$username.
  '"');

if (mysql_num_rows($result) > 0) {
  echo 0;
} else {
  echo 1;
}

?>

Answer 1

I finally found the solution. The problem was not from the jQuery or the php script, i only changed the way i call the function in the form from : onkeyup to onchange, and it is now working like a charm. I hope this tip avoid to others losing hours of time like it did to me. Thank's guys for your suggestions.

Answer 2

If you are getting 500 error that there is problem with the database connection. check for the included files and connection variables used for database connection.

Hope that will work.