Javascript querying xml files

I'm looking for some custom javascript to extract data from an xml file and use it to print html.

I want to insert a call to the javascript into the html of a blog post, specify three variables, and have the javascript print the html -example attached.

The javascript will make use of existing xml files which contain the required data - example attached

I want to set three variables: (location_id), (image_class), (caption)

The javascript will use the location_id variable to find the correct xml file

The javascript will extract the information for the first image in the xml file.

The javascript will write the html to the blog post.