$ _GET JavaScript和AJAX…

Question

I am relatively new to PHP and I am (trying to) developing my first AJAX code...

I am trying to pass an attribute from a select with several options, each option with its very own unique attribute "values" that is a String.

The PHP file GETs the value and does something with it (for instance prints it out). And the generated file is then returned to my main HTML page.

Here is the source code...

Here is my javaScript:

function showUser(myElement) {

    var str = myElement.options[myElement.selectedIndex].getAttribute("values");

    if (str == "") {
        document.getElementById("myResponse").innerHTML = "";
        return;
    } else { 
        if (window.XMLHttpRequest) {
            // code for IE7+, Firefox, Chrome, Opera, Safari
            xmlhttp = new XMLHttpRequest();
        } else {
            // code for IE6, IE5
            xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        }
        xmlhttp.onreadystatechange = function() {
        if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
            document.getElementById("myResponse").innerHTML = xmlhttp.responseText;
            }
        }
        xmlhttp.open("GET","getuser.php?q="+encodeURIComponent(str),true);
        xmlhttp.send();
    }
}

My HTML is as following:

<form>
<select name="users" onchange="showUser(this)">
  <option values="">Select a person:</option>
  <option values="Rasmus Lerdorf">Creator of PHP</option>
  <option values="Linus Torvalds">Developed Linux</option>
  <option values="Dennis Ritchie">Developper of C</option>
  </select>
</form>
<br>
<div id="myResponse"><b>Person info will be listed here...</b></div>

My PHP is:

<?php
$q = intval($_GET['q']);
echo $q;
?>

I get 0 instead of the text string, what is wrong with my code?

Answer 1

Silly me,

I copied and pasted a basic example from a tutorial and I did not realize that the PHP code was casting the string that was sent over the GET to an integer.

$q = intval($_GET['q']);

The code should be :

$q = $_GET['q'];

On my earlier stage of the development I was indeed passing an integer, so the code was working.

The code returned 0 instead of an error because the intval of a string is 0 on failure.

Writing down the question here I realized the mistake...