export e Json Data

[mermi]

Hello, i used Rgraph example to draw a graphe , i passed tha init function with a param "id" and with this id in the init function i want to export the Json file from /Data
function init(id){

//init data

var json = $.getJSON("Data/"+id+".json");
alert(json[1]);}the alert appear empty. how can i export a Json File ?!