Question

I’ve trying to send some infromation to a php file and display the result returned. First of all I’m not receiving any results from php file i.e. no value in xmlhttp.responseText. Instead of responseText, I tried putting 'something else' which made no difference. But when i comment out //if (xmlhttp.readyState==4 && xmlhttp.status==200), the result briefly appears.
What have I done wrong?

Ajax code looks like this:

var div = 'display';
var xmlhttp;
if (window.XMLHttpRequest)
{
    xmlhttp=new XMLHttpRequest();
 }
else
{
    xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}

xmlhttp.onreadystatechange=function()
{
    if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
        writeBack (div, xmlhttp.responseText+'something else', 'red');
    }
}

xmlhttp.open("POST","update_profile2.php",true);
xmlhttp.setRequestHeader("Content-type","application/x-www-form-urlencoded");
xmlhttp.send("rr="+id);

Php code:

..
if(isset($_POST['rr']))
{
die('connection made');
}
..

Answer 1

Every problem I’ve ever had with AJAX is usually caused by trying to submit an AJAX request using a ‘submit’ button in a form. If you are doing that, make sure you stop the .submit() …. Also, if you use jQuery, your AJAX code will look sooooo much better 🙂