Trouble with XMLHttpRequest in javascript

[gradinafrica]

I'm trying to create a log out button that uses AJAX to call a php file which ends the current session:

//logout.php
<?php
    if (!session_start());
    session_destroy(); //Destroys the session
    echo "success";
?>
 

When I put this in the function that calls logout.php, it says that there is a type mismatch on line 32 of doLogout.js (the script used to call logout.php):

//erroneous file
var httpobj = null;
function dothis()
{
}
// Get the HTTP Object
function obje(){
if (window.ActiveXObject) return new ActiveXObject("Microsoft.XMLHTTP");
else if (window.XMLHttpRequest) return new XMLHttpRequest();
else {
alert("Your browser does not support AJAX.");
return null;
}
}
// Change the value of the outputText field
function setthis(obj,link){
if(httpobj.readyState == 4){
if (httpobj.responseText=="success")
{
    document.getElementById(obj).innerHTML = "<a href='page.php?type=login' class='"+link+"'>Login</a>  |  <a href='page.php?type=register' class='"+link+"'>Register</a>";
} else {
    alert("Failed to log out!!!");
}
}}
// Implement business logic
function logout(obj,link){
httpobj = obje();
if (httpobj != null) {
var parameters = "nothing=nothing";
httpobj.open("GET", "ajax/logout.php", true);
httpobj.send(parameters);
httpobj.onreadystatechange = setthis(obj,link); //The ill-fated line 32.
}}
 

But when I put a simple 'alert();' above line 32, it works the exact way that I want it to, except for an annoying little prompt that pops up:

var httpobj = null;
function dothis()
{
}
// Get the HTTP Object
function obje(){
if (window.ActiveXObject) return new ActiveXObject("Microsoft.XMLHTTP");
else if (window.XMLHttpRequest) return new XMLHttpRequest();
else {
alert("Your browser does not support AJAX.");
return null;
}
}
// Change the value of the outputText field
function setthis(obj,link){
if(httpobj.readyState == 4){
if (httpobj.responseText=="success")
{
    document.getElementById(obj).innerHTML = "<a href='page.php?type=login' class='"+link+"'>Login</a>  |  <a href='page.php?type=register' class='"+link+"'>Register</a>";
} else {
    alert("Failed to log out!!!");
}
}}
// Implement business logic
function logout(obj,link){
httpobj = obje();
if (httpobj != null) {
var parameters = "nothing=nothing";
httpobj.open("GET", "ajax/logout.php", true);
httpobj.send(parameters);
alert();//The annoying little prompt.
httpobj.onreadystatechange = setthis(obj,link);//The ill-fated line 32.
}}
 

What happens when alert() is called that would make this work?
Basically what I'm tryin to have it do is when it is clicked, it passes its id and the id of it's parent node to a function which terminates the session and then changes the innerHTML of the parent node to a different link (a log in link - since they just logged out) which has the same css as the clicked link.
That's a mouthful, but it should be pretty simple. I've quintuple-checked this script and I can't find any errors or any reason for calling alert() to make it work.

Let me know what you figure out.

Gradinafrica

[Plater]

the function you assign to the onreadystatechange cannot have parameters.

Example:

http.onreadystatechange = handleSendUpdateReponse;
 
function handleSendUpdateReponse()
 

I think you can get away with doing:

httpobj.onreadystatechange = function{setthis(obj,link);}
 

See if that helps you

[Dormilich]

should be rather

httpobj.onreadystatechange = function() { setthis(obj,link); }

or (which is essentially the same)

var tempFn = function() { setthis(obj,link); }
httpobj.onreadystatechange = tempFn;