getJSON Does not work ?

Hey, i wanna create a dynamic edge animate - animation

So i've tried to load in a json file without any success...

My *.json file is in the same directory as the edge files - my example code:

$.getJSON('source.json', function(data) {                    alert("Inside GETJSON");                    for ( var i=0; i < data.length; i++){                       // console.log("data[i]");                    }          });

Nor the alert is triggered, neither the log in console... :/ I've places my code in the composition complete section of my edge-project. (I'm not sure - is that the problem?)

Any hint or help would be great