Checking if user exists jquery validator,ajax and codeigneter

Question

I m trying to check if a username exists or not but even if the username doesn't exists it keeps saying "Username already exists" this is my javascript code:

$.validator.addMethod("checkUsername", 
    function(value, element) {
        var test = "";
        $.ajax({
            type:"GET",
            url: site_url + "/ajax/checkusername/" + value,
            success: function(result){
               if(result=="exists")
                   return false;
               else
                   return true;
            }
        });
    }, 
    "Username Already Exists."
);



    $("#myform").validate({
        rules: {
            username2: {
                required: true,
                minlength: 6,
                checkUsername:true
            },
            password2: {
                required: true,
                minlength: 6
            },
            email: {
                required: true,
                email: true
            }
        }
    });
});

This is my controller code:

public function checkusername($username)
{
            $this->load->model('user_model');
            $user = $this->user_model->getUser($username);
            if($user == null)
            {
                echo json_encode("notexists");
            }
            else
            {
                echo json_encode("exists");
            }  
}

Any Ideas about this how this can be solved? Thanks in advance.

Answer 1

Why are you encoding the response as JSON when you're not parsing JSON with your ajax ?

What happens when you simply do this?:

public function checkusername($username)
{
        $this->load->model('user_model');
        $user = $this->user_model->getUser($username);
        if($user == null)
        {
            echo "notexists";
        }
        else
        {
            echo "exists";
        }  
}

---

EDIT :

$.validator.addMethod("checkUsername", 
    function(value, element) {
        var result = false;
        $.ajax({
            type:"GET",
            async: false,
            url: site_url + "/ajax/checkusername/" + value,
            success: function(msg) {
                result = (msg == "exists") ? false : true;
            }
        });
        return result;
    }, 
    "Username Already Exists."
);

Answer 2

$.ajax read a string. Cause you do echo json_encode this string is json.

You can use $.getJSON in stead of $.ajax

$.getJSON( site_url + "/ajax/checkusername/" + value, function( json ) {
  if(json=="notexists"){alert('Not exists')}
 });

or add $.parseJSON to your original code:

  if($.parseJSON(result)=="exists")

update: i had to change my answer your function doesn't return the result of your $.ajax . $.ajax had to set your return value. Cause can't return before your ajax has been finished, you also have to add async: false to your request (see: How do I make jQuery wait for an Ajax call to finish before it returns? )

$.validator.addMethod("checkUsername", 
    function(value, element) {
        var test = false;
        $.ajax({
        type:"GET",
        async: false,
        url: site_url + "/ajax/checkusername/" + value,
        success: function(result){
           if(result=="notexists") {test = true; }       
           }
    });
    return test;
    }, 
    "Username Already Exists."
);