base_url() and javascript

[eluser]0plus1[/eluser]
I have the need to mantain a project in two direction, a sandbox copy and a live version. The live version has a different directory structure so in javascript I need to change all the ajax calls:

/sandbox/controller/method

to

/controller/method

all this useless work could be simplified by using:

<?=base_url();?>controller/method

Problem is that the js is in a javascript file.

Is there a reccomended way to use base_url with javascript? I understand I could use: javascript.php problem is that with codeigniter I have to create a controller then a view.

Are there workaround / elegant way to achieve this?

Thank you