In wordpress request.open('GET', 'data.json',true); not working! why?

Hi i am making a WordPress plugin that can bring the names of products from json file if someone writes products name into the search bar. But i think data.json is not getting by Ajax in WordPress. its path defining syntax error i guess.

$.getJSON('data.json', function(data)

following is complete scripting code and it was working fine in PHP website but not in WordPress.:

jQuery('#search').keyup(function(){
var searchField = jQuery('#search').val();
var myExp = RegExp(searchField,"i");
jQuery.getJSON('data.json', function(data){

    var output= '<ul class="SearchResult">';
    jQuery.each(data, function(key, val){
        if((val.name.search(myExp) != -1) || (val.category.search(myExp) != -1)){
            output += '<li>';
            output += '<h2>' + val.name + '</h2>';

            output += '<img src="images/'+val.image+'.jpg" alt="sorry for image"/>';

            output += '<p>' + val.category + '</p>';
            output += '</li>';
        }
    });
    output += '</ul>';
    jQuery('#update').html(output);

});
});