Question

Had a nice PHP/HTML/JS prototype working on my personal Linode, then tried to throw it into a work machine.

The page adds a script tag dynamically with some JavaScript. It’s a bunch of Google charts that update based on different timeslices. That code looks something like this:

// jQuery $.post to send the beginning and end timestamps
$.post("channel_functions.php", data_to_post, function(data){
   // the data that's returned is the javascript I want to load
   var script = document.createElement('script');
   var head= document.getElementsByTagName('head')[0];
   var script= document.createElement('script');
   var text = document.createTextNode(data);
   script.type= 'text/javascript';
   script.id = 'chart_data';
   script.appendChild(text);
   // Adding script tag to page
   head.appendChild(script);
   // Call the function I know were present in the script tag
   loadTheCharts();
});

function loadTheCharts() {
   // These are the functions that were loaded dynamically
   // By this point the script tag is supposed be loaded, added and eval'd
   function1();
   function2();
}

Function1() and function2() don’t exist until they get added to the dom, but I don’t call loadTheCharts() until after the $.post has run so this doesn’t seem to be a problem.

I’m one of those dirty PHP coders you mother warned you about, so I’m not well versed in JavaScript beyond what I’ve read in the typical go-to O’Reilly books. But this code worked fine on my personal dev server, so I’m wondering why it wouldn’t work on this new machine.

The only difference in setup, from what I can tell, is that the new machine is running on port 8080, so it’s 192.168.blah.blah:8080/index.php instead of nicedomain.com/index.php.

I see the code was indeed added to the dom when I use webmaster tools to “view generated source” but in Firebug I get an error like “function2() is undefined” even though my understanding was that all script tags are eval’ed when added to .

My question: Given what I’ve laid out, and that the machine is running on :8080, is there a reason anyone can think of as to why a dynamically loaded function like function2() would be defined on the Linode and not on the machine running Apache on 8080?

Answer 1

jQuery supports javascript responses:

$.post("channel_functions.php", data_to_post, 
       function (data, textStatus, xhr) {loadTheCharts()}, 
       'script');

However, a dataType of “script” will turn a cross-domain POST into a GET, as per the documentation.

The main problem with eval is the eval-ed code inherits the scope the eval is in. Instead, you can use jQuery.globalEval. Try something like:

$.post("channel_functions.php", data_to_post, 
       function (data, textStatus, xhr) {
           /* data might have errors, which will cause an exception.
              We'll let the default exception handler catch & log it.
            */
           $.globalEval(data);
           loadTheCharts();
       });