How to access a specific file in your plugin

Hello,

i am trying to use FCBKcomplete in a WordPress plugin. Here is an example of how to use a javascript piece to implement that:

$("element").fcbkcomplete({
json_url: "fetched.txt",
cache: true,
filter_case: true,
filter_hide: true,
newel: true
});

now, json_url is a file in my plugin directory that contains the list of names for the auto-suggest. How can i point that file? I can’t figure out how to point a relative path from within my plugin.

Thanks in advance.