Ajax Class Efficiency

So I wrote this class to handle my ajax calls simply:

ajaxCon.php:

class ajaxCon{
    private $init = false;
    private $functionArray = array();
    private $Message = false;
    private $function = null;
    private $arguments = null;
    private $post = null;

    public function __construct(){
        if(!isset($_POST['ajaxRequest'], $_POST['ajaxFunction'])) return;
        $this->init = true;
        ob_start();
        $this->post = $this->sanitizeArr($_POST);
        $this->arguments = $this->sanitizeArr($_POST['arguments']);
        $this->function = $_POST['ajaxFunction'];
    }

    public function addFunction($functionName, $functionCode){
        if(!$this->init || !isset($functionName, $functionCode) || $functionName != $this->function) return $this;
        $this->Message = call_user_func_array($functionCode, $this->arguments) ? 'success' : 'fail' ;
        unset($this->init, $this->functionArray, $this->post);
        $returnVars = get_object_vars($this);
        ob_clean();
        echo json_encode($returnVars);
        ob_flush();
        exit();
    }

    private function sanitizeArr($returnArr, $sanitizer = 'sanitize_sql_string') {
        array_walk_recursive($returnArr, function (&$value) use ($sanitizer) {
            $value = $sanitizer($value);
        });

        return $returnArr;
    }
}

ajaxCon.js:

function ajax() {

    this.callback = false;

    this.ajaxFailure = function (returnData) {};

    this.ajaxSuccess = function (returnData) {};

    this.call = function(functionName, argumentArray, callback){
        $.ajax( $.extend(true, {}, this.ajaxSettings, {data:{'ajaxFunction':functionName, 'arguments':argumentArray}} ) );
        this.callback = callback;
    };

    this.ajaxReturn = function (returnData){
        returnData = returnData.substring(returnData.indexOf("{") - 1);
        returnData = returnData.substring(0, returnData.lastIndexOf("}") + 1);
        var responseArray = $.parseJSON(returnData);

        if (responseArray.Message.toLowerCase() != "success"){
            this.ajaxFailure(responseArray);
            return;
        }

        this.ajaxSuccess(responseArray);
        if(this.callback != false) this.callback(responseArray);
    };

    window.ajaxCon = this;
    this.ajaxSettings = { url: window.location.href, type: 'POST', cache: false, data: {ajaxRequest: true}, success: function (returnData) {
        ajaxCon.ajaxReturn(returnData)
    }};
}

and you call it like so:

<?php
    $ajaxCon = new ajaxCon;

    $ajaxCon->addFunction('checkEmail', function($Email){
        global $ajaxCon;
        if(emailIsInDB($Email)) $ajaxCon->hasAccount = true;
        return true;
    });
?>
<script type="text/javascript">
    var ajaxCon = new ajaxCon();

    function checkEmail() {
        ajaxCon.call('checkEmail', {'Email':$('#Email').val()}, function(result){
            if(!result.hasAccount) $('#SignUp').submit();
        });
    }
</script>

The drawbacks I know of are lot’s of preprocessing (The entire page has to be preprocesed) and the page then executes as normal until the php function I need is defined and called.

Any ideas on how I can optimize the code and make it run more efficiently while preserving/improving readability?

A review of the JavaScript part:

• ajaxCon is a class/constructor, so you should call it AjaxCon, though really I would think about finding an even better name 🙂
• ajaxFailure -> You have a number of functions that have ajax in their name, since these functions are in the Ajax constructor you can drop the ajax part
• this.callback = false; -> Don’t declare callback at all and then use
  if(this.callback) this.callback(responseArray);

• This could use some newlines:
  $.ajax( $.extend(true, {}, this.ajaxSettings, {data:{'ajaxFunction':functionName, 'arguments':argumentArray}} ) );

  and also

  this.ajaxSettings = { url: window.location.href, type: 'POST', cache: false, data: {ajaxRequest: true}, success: function (returnData) {
      ajaxCon.ajaxReturn(returnData)
  }};
  

• Also the location of this.ajaxSettings is odd, this belongs on top of that function

Review for the PHP part:

• What problem does your class solve? Are you not doing too many things in one class? If your goal is to handle incoming Ajax requests, then a different object should handle the response.
• Class names should be in CamelCaps, i.e. AjaxCon.

• If you need something in your constructor (data from POST, etc), just ask for it in the constructor:

  public function __construct(array $post) {
  

• Don’t try to sanitize the entire $_POST array at once, it never works. What are you sanitizing it for? Data that goes into the database should go through prepared statements, data that gets outputted back to the page as HTML should be run through htmlspecialchars() before they are outputted to the page. Don’t sanitize data until the moment you need it, otherwise you risk double sanitation problems (Tom & Jerry becomes Tom & Jerry which becomes Tom & Jerry, oops).

• Don’t output in your function. Always return. Output should be on a single place only, and that’s at the very end of the run, where you need to return the response after all processing is done.
• Don’t use get_object_vars($this) for the purpose you are using it. Specify exactly what variables you are returning, it’s more readable.

• Don’t use globals – If you need to pass a variable from the outside to an anonymous function, use use:

  function($email) use ($ajaxCon) {
  

• DO NOT USE GLOBALS – Seriously, don’t.