AJAX and javascript calling javascript

[krnl]

I am using (or attempting to use, anyway) an AJAX solution for use in posting client-side information to update database values on my website. I have the AJAX portion working and calling a page to process the database update, but I'm having problems getting the values from the client-side javascript to use in my local AJAX javascript function.

For instance, I run website www.aaa.com, and within my site, there is a call to a javascript at an external website, bbb.com which I use to display certain information within my site.

So, I call bbb.com's javascript as such:

<script type="text/javascript"
    src="http://www.bbb.com/jsfunction.js?a=30&key=deadbeef"></script>

Now, I want to take the return value (an integer ranging from 0-1000) from the above javascript call and place use it in a variable within my local javascript. Can this be done?

Something like:

<script type="text/javascript">
var key = "<?= $item_key ?>";
var xyz = document.write("<script type='text/javascript' 
   src='http://www.bbb.com/jsfunction.js?a=30&key="'+key+'"><\/script>');

ajaxFunction('update', xyz);
</script>

Any pointers you all can give would be greatly appreciated.

Thanks.

[wige]

If the javascript you are calling is a function that returns a value, you should be able to capture the return value the same as you would in a local function call.

<!-- Include the Javascript containing the target function -->
<script type="text/javascript" src="http://remoteserver/remote.js"></script>
<script type="text/javascript">
   // Set the variable to be passed to the remote function
   var key="x";
   // Call the remote function, and store the return value in another variable
   var value = remoteFunction(key);
</script>

And for those of you that are wondering, yes, to bbb.com, this would be an exploit of a cross site scripting vulnerability. Javascript bad.

[kgun]

What makes this AJAX? Where is the asynchronous communication with the server? A time now since I looked at AJAX, but can you use the XMLHttpRequest Object that is used for asynchronous communication with the server?

Also note that DOM is intimately integrated with the X (XML) part of AJAX. Very much can be done with DOM functions and more specifically with DOM XML functions.

No need to reinvent the wheel.

[krnl]

The ajax function is defined earlier in the file and uses the xmlhttprequest mechanism to call a local php script that will take care of the database update. The call to the ajax function follows the javascript stuff with ajaxFunction('update', var1, var2); where var1 is the key and var2 is the output from the remote javascript call.

function ajaxFunction(action,var1,var2) {
    http.open('get', 'rpc.php?action='+action+'&var1='+var1+'&var2='+var2);
    http.onreadystatechange = handleResponse;
    http.send(null);
}

I am getting everything to pass correctly to the AJAX function except the previously noted remote javascript call. The remote javascript outputs the following: document.write('32'); - or whatever number...I need that number for var2 of my AJAX function call.

If I'm reinventing the wheel and going about this all wrong, then please tell me what the proper approach is.

Thanks for your feedback! I look forward to hearing more!

[kgun]

As I told you, I am a bit away from AJAX now, but note that Google combines Remote Scripting with IFRAME with the XMLHttpRequest object as far as I know to get the best combination of both worlds.

I am not sure that that solves your problem though, and I can not, as I told be more specific now. Will take me some hours to repeat that stuff.

[krnl]

kgun, I do appreciate your input. I'll keep reading with a couple of the links that are provided in your post.

If anyone else has any thoughts on how to accomplish my objective, please let me know!

Thanks!

[kgun]

I know where I would have looked. In one of the following to books that I have here:

1. Professional AJAX NCZOnline - The Official Web Site of Nicholas C. Zakas
2. Building Responsive Web Applications. AJAX and PHP. Christian Daire et al.

[mikmik]

[url="http://www.devshed.com/c/a/Security/A-Quick-Look-at-Cross-Site-Scripting/1/"] A Quick Look at Cross Site Scripting - What is Cross Site Scripting?[/ur]

BTW, there is a way to serve php with ajax, but I havent found it yet, but for now, this site is excellent, here are some:
[url="http://www.devshed.com/c/a/PHP/Creating-AJAX-Requester-Objects-with-Abstract-Factory-Classes-in-PHP-5/"]Creating AJAX Requester Objects with Abstract Factory Classes in PHP 5 [/ur]

[url="http://www.devshed.com/c/a/PHP/PHP-Datastorage-Class/1/"] PHP Datastorage Class[/ur]

Before we get into the nitty-gritty of XML parsing with PHP, I'd like to take some time to explain how all the pieces fit together.
[url="http://www.devshed.com/c/a/XML/Using-PHP-with-XML-part-1/1/"]Using PHP with XML [/ur]
[url="http://www.devshed.com/c/a/PHP/PHP-and-JavaScript-Interaction-Storing-Data-in-the-Client-part-1/"]PHP and JavaScript Interaction: Storing Data in the Client [/ur]
[url="http://www.devshed.com/c/a/PHP/Creating-AJAX-Requester-Objects-with-Abstract-Factory-Classes-in-PHP-5/1/"] Creating AJAX Requester Objects with Abstract Factory Classes in PHP 5 - Working with AJAX HTTP requester objects[/ur]

This guy is excellent, I mean excellent. Ho has a tute on serving php dynamically with javascript, etc..
[url="http://www.devshed.com/cp/bio/Alejandro-Gervasio/"]Alejandro Gervasio [/ur] but I cannot find them. I have on my back-ups somewhere, and will get.

I also used PEARL libraries to do what you want to do. I have been out for two years, but I know it has been done, don't need to re-invent! I did it with ajax and xml as well as MySQL db when dooing google maps programming.

Basically, you can put ajax into a <div> and read and write there dynamically without re=generating your whole page.


More specifically, in this second article of the series, I'm going to demonstrate how to apply the abstract factory pattern to create diverse AJAX HTTP requester objects, which can be used in distinct contexts.
[url="http://www.devshed.com/c/a/PHP/Creating-AJAX-Requester-Objects-with-Abstract-Factory-Classes-in-PHP-5/"]Creating AJAX Requester Objects with Abstract Factory Classes in PHP 5 [/ur]

I'll be back later with a staright forward solution... Basically parsing js and extracting the var, then using echo to write the js withthe var included.

(WTF?)

[DaveSawers]

Why would you want to cross call a Javascript file from another site? Why not just load the file onto your site and avoid all the problems?

[kgun]

"Cross server scripting", a potential security risk or am I wrong when done by the webmaster him/her self?

zXml 1.0.2

A JavaScript library for cross-browser XML, XPath, and XSLT support. (24 KB)

One of the best JS libraries for AJAX I know off. There are other on the page:

NCZOnline - Downloads