how to parse data from json file using java script

Question

how to parse data from json file using java script?

how to parse data from json file using java script i Got only empty alert box in json file.how to retreive full content of json file data

<select onchange="calTest()" id="sle">
    <option>Peter</option>
    <option>Zara</option>
    <option>one</option>
</select>
<input type="text" id="txt">
<!-- http://jsfiddle.net/ifaour/S4YYk/1/ -->

<!-- http://ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js -->
<script src="jquery.js"></script>
<script>
    function calTest() {
        var aname = document.getElementById("sle").value;

        var json = "";

        $.getJSON("test/test.json", function(data) {
            json = data;

        });
        alert(json);
        $.each(json, function(i, v) {

            if (v.name == aname) {
                document.getElementById("txt").value = v.age;
                alert(v.age);
                return;
            }
        });

    }
</script>

Answer 1

$.getJSON is async that means it is called after the alert... so json is still empty.

Try

$.getJSON("test/test.json", function(data) {
      json = data;
      alert(json);
});