How To (Effectively) use jQuery to Match the Value of an Input with a Database?

I've been working on a PHP project of mine, and I am attempting to add a feature that tells the user whether or not the username they entered in a register form is already taken as they update the input. When starting this, I thought I knew how to code this- but I ran into some problems along the way.

When I post the data to my PHP script, I get the 'all clear'. I've double checked it, as well as FireBugged the post- all variables are present, and the server returns exactly as expected. I've inserted a test field into my database so I can see if it works. The name in the DB is 'Cameron'.

Now, for my code.

function checkUsername() {
    $.post(rootpath + "/inc/php/handlers/checkusername.php", {
        submit: "submitted",
     开发者_高级运维   username: $('#username').val()
    }, function (data) {
        if (data = 'not_taken') {

            $('#cui').html('<img src="' + rootpath + '/inc/images/icons/Checkmark-32.png" />');
        }
        else {
            $('#cui').html('<img src="' + rootpath + '/inc/images/icons/block-icon-32.png" width="32" height="32" />');
        }
    }, "html");
}

and then

<input type='text' name='username' id='username' onkeyup='checkUsername();' />

In this case, I was hoping to change the HTML of a div to that of an image. But what the code does is switch to the checkmark image (the first one), regardless of the return (see below).

I believed this was a problem with the method I used for updating the div, .html(). But I then discovered that, even if the first combination submitted was that of the database (returning 'taken'), the output would still be the check-mark image.

I need the image to update with, obviously, the correct one. I'm pretty sure it's not a PHP problem as the script I set up returns the data expected.

Thanks in advance for any help!

You're using the assignment operator instead of checking for equality in your conditional:

if(data = 'not_taken') {

should be

if(data == 'not_taken') {

function doAjaxPost(username)
      { 

        var username= $('#username').val();


        $.ajax({  
           type: "POST",  
            url: "/inc/php/handlers/checkusername.php",  
            data: "username="+username+,   
            success: function(resp){  
             //alert($Msg);   
    },  
         error: function(e){  
            //alert($Msg);  
  }  
 });  
 }

in checkusername.php

$SelectQuery=" select usename from userswhere usename='".$_POST['usename']."' ";
                    if($Row=$DB->Select($SelectQuery,'select_capacity',$Module))
                    {
                      $select_record=1;
                    }
                    $sbval=mysql_num_rows($Row);
                    if($sbval>=1)
                    return  "alreay exist";

It will be done in this way . show finel returned message in response div.

It's a way to do. Please change the code according to ur CMS ,architecture,framework.

I hope it will help u. cheers :)

enter code here