JQuery - Storing ajax response into global variable

Question

Im still somewhat of a newbie on jQuery and the ajax scene, but I have an $.ajax request performing a GET to retrieve some XML files (~6KB or less), however for the duration the user spends on that page that XML content should not / will not change (this design I cannot change, I also don't have access to change the XML file as I am reading it from somewhere else). Therefore I have a global variable that I store the response data into, and any subsequent look ups on the data are done on this variable so multiple requests don't need to be made.

Given the fact that the XML file can increase, Im not sure this is the best practice, and also coming from a java background my thoughts on global public variables are generally a no-no.

So the question I have is whether there might be a better way to do this, and a question on whether this causes any memory issues if the file expands out to some ridiculous file size?

I figure the data could be passed into a some getter/setter type functions inside the xml object, which would solve my global public variable problems, but still raises the question on whether I should store the response inside the object itself.

For example, what I currently do is:

// top of code
var xml;
// get the file
$.ajax({
  type: "GET",
  url: "test.xml",
  dataType: "xml",
  success : function(data) {
    xml = data;
  }
});
// at a later stage do something with the 'xml' object
var foo = $(xml).find('something').attr('somethingElse');

Answer 1

Here is a function that does the job quite well. I could not get the Best Answer above to work.

jQuery.extend({
    getValues: function(url) {
        var result = null;
        $.ajax({
            url: url,
            type: 'get',
            dataType: 'xml',
            async: false,
            success: function(data) {
                result = data;
            }
        });
       return result;
    }
});

Then to access it, create the variable like so:

var results = $.getValues("url string");