Retrieving json through a url using ajax

I have this method that looks for the data that is in a txt file and populates a table:

$(document).ready(function () {
    $('#example').DataTable({
        "ajax": "objects.txt",
        "columns": [
            { "data": "name" },
            { "data": "position" },
            { "data": "office" },
            { "data": "extn" },
            { "data": "start_date" },
            { "data": "salary" }
        ]
    });
});

How can I modify this method to fetch a url, which returns a json?

this is the url: link