Username live check using Ajax PHP - php

Question

I have a code in which there's a function which is supposed to check if a username is available or not.
I'm confused about how this function works.
JS:
jQuery(document).ready(function(){
// binds form submission and fields to the validation engine
jQuery("#register-form").validationEngine();
});
HTML input:
<form action="" id="register-form">
<input value="" class="validate[required,custom[onlyLetterNumber],maxSize[20],ajax[ajaxNameCallPhp]]] input" type="text" name="username"/>
</form>
This is my JS function:
(function($){
$.fn.validationEngineLanguage = function(){};
$.validationEngineLanguage = {
newLang: function(){
$.validationEngineLanguage.allRules = {
"ajaxNameCallPhp": {
// remote json service location
"url": "ajaxNameCallPhp.php",
// error
"alertText": "* This name is already taken",
// speaks by itself
"alertTextLoad": "* Validating, please wait"
}
};
}
};
$.validationEngineLanguage.newLang();
})(jQuery);
and this is my ajaxNameCallPhp.php function:
include ("config.php");
$username = trim(strtolower($_POST['username']));
$username = mysql_escape_string($username);
$query = "SELECT username FROM user WHERE username = '$username' LIMIT 1";
$result = mysql_query($query);
$num = mysql_num_rows($result);
echo $num;
mysql_close();
So anyone can give me a solutions ?
I appreciate and thanks with your attention.
Thank you.

Answer 1

try this
function UserNameExist(){
$("#msg").html( "* Validating, please wait" );
$.ajax({
url: "ajaxNameCallPhp.php",
type: "POST",
data: {username : $('#username').val()},
dataType: "html"
}).done(function(msg) {
if(msg > 0){
$("#msg").html( "* This name is available" );
}else{
$("#msg").html( "* This name is already taken" );
}
});
}
where #msg is the id of the div where you show your massage
and #userName is the id of the text box
hope that help.