I'm trying to modify a function to make an Ajax request directly from an XML file, rather than have a server side script in the middle.

However, the function 'ajaxRespose' doesn't seem to be getting called, I think the problem is the line with:

ajaxReq.open ('GET', filename);

I'm guessing the 'GET' shouldn't be there, although I've tried omitting it but have had no luck.

Here is the function I am using:

function ajaxRequest (filename)
    {
        var ajaxReq = false;
        
        try 
            {
                var ajaxReq = new XMLHttpRequest (); }
        
        catch (err)
            {
                ajaxReq = false; }
        
        ajaxReq.open ('GET', filename);
        ajaxReq.onreadystatechange = ajaxResponse;
        ajaxReq.send (null);
    }

Note: the value of the 'filename' variable will be 'data.xml', and I have ensured that the file does exist in the directory.

var ajaxReq = new XMLHttpRequest (); will only work in FF & Opera

ajaxReq.onreadystatechange should point to a function that does something the returned data.

Could post the code for ajaxResponse? When you say it's not being called do you know that it's not being called or it's just not doing anything? Could be it's not grabbing the info from the XML file properly.

Thanks, yeah here it is:

function ajaxResponse ()
    {
        if (ajaxReq.readyState != 4)
            {
                return; }
        
        if (ajaxReq.status == 200)
            {
                if (ajaxCallBack)
                    {
                        ajaxCallBack ();
                    }
            }
        
        else
            {
                alert ('Request Failed: ' + ajaxReq.statusText);
            }        
    }

// gather student details

// assign xml filename
function fileAssign ()
    {
        var filename = 'data.xml';
        ajaxCallBack = tableBuild;

        // request data
        ajaxRequest (filename);
    }

function tableBuild ()
    {
        var stu = ajaxReq.responseXML.getElementsByTagName ('name');
        alert (stu[0].firstChild.nodeValue);
    }

fileAssign ();

I've included the following functions aswell, just in case
Also, I think the ajaxResponse function isn't being called because I added a simple alert at the start of the function, which wasn't displayed.

var ajaxReq = false; in a function, would declare a local variable, only available to that function.
So you either have to remove the var keyword, or pass the variable along with calling the next function.

And ajaxReq.open(); takes three arguments:
- method
- file
- asynchronous (true/false)

Originally Posted by Insensus

var ajaxReq = false; in a function, would declare a local variable, only available to that function.
So you either have to remove the var keyword, or pass the variable along with calling the next function.

And ajaxReq.open(); takes three arguments:
- method
- file
- asynchronous (true/false)

Hmmm that's strange, because I've used the script before with the var keyword and it's worked. The only difference with this one really is that I'm not reading from a PHP file.

I've tried ajaxReq.open with the 'POST' method but that didn't work either (although I wasn't expecting it to anyway!)

The point you seem to be missing is that in your code ajaxReq isn't going to exist in ajaxResponse() because it is a local variable to ajaxRequest()

move the instantiation of the variable outside of the function and it will work (but only in firefox)

http://www.modtalk.co.uk/_site/code/javascript/getxml/

At last it works! Thanks. Turns out the code in the book I have was the way you said to do it... only I read it wrong!