[RESOLVED] php with javascript? check if username is taken

i'm making a registration form and i want it to check if the username has been taken while the user is registering (before the user submits the form)

how to do this?

Just a quick thought

1) On the onBlur event of the username field
2) Use xmlhttprequest to fire your username to a php script (e.g. 'http://domain.com/checkUsername.php?username'+element.value)
3) Using PHP, check the usernames status, return this value
4) Depending on the result output either a success of failure message

Sorry I cannot provide an example right now, but Googling these stages should sort you out, post back with any problems you may have.

thats a good tip, i will do some searching and return here :)

Hi,
I recently made an registration form, and checks for the existing username using AJAX. Try this.

Code:

---

function exists_username(field)
{
        if (window.XMLHttpRequest)
        {
                  XMLHttpRequestObject = new XMLHttpRequest();
        }
        else if (window.ActiveXObject)
        {
                XMLHttpRequestObject = new ActiveXObject("Microsoft.XMLHTTP");
        }
        field = field.value;
        var url = "functions.php?ud="+ field;
        if(XMLHttpRequestObject)
    {
        var obj = document.getElementById("v1"); //to display the error message as "Username already taken"
      XMLHttpRequestObject.open("GET", url,false);
      XMLHttpRequestObject.onreadystatechange = function()
      {
        if (XMLHttpRequestObject.readyState == 4 &&
          XMLHttpRequestObject.status == 200)
          {
                if(XMLHttpRequestObject.responseText=="Username Already Exists") 
                {
                                obj.innerHTML = XMLHttpRequestObject.responseText;
                                return false;//but this is not returning as false.                               
                        }
                        return false;
          }
      }
      XMLHttpRequestObject.send("");
    }
}

---

functions.php

Code:

---

//connection to the host&database
$query = "SELECT username
                          FROM users
                          WHERE username='$ud';";
        $result = mysqli_query($dbconn,$query);
        if(mysqli_num_rows($result)>1)
        {echo "Username Already Exists";}

---

I would personally advise you find a tutorial about ajax and use that instead of using any of the code posted above.

yeah thats what i will do too, otherwise i won't learn much of it..

Quote:

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Originally Posted by kows

I would personally advise you find a tutorial about ajax and use that instead of using any of the code posted above.

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The code is also vulnerable to SQL injection; uses register globals and sends reduncdant information. Prehaps its best to delete the entire post.