ajax-util.js

(
    function(global) {
        
        var ajaxUtils ={};

        function getRequestObject() {
            if (window.XMLHttpRequest) 
                return ( new XMLHttpRequest() ) ;

            else {
                console.log ("AJAX not supported");
                return(null);
            }
        }

        ajaxUtils.sendGetRequest = 
            function(requestUrl, responseHandler, isJsonResponse) {
                var request = getRequestObject();
                request.onreadystatechange =
                    function() {
                        handleResponse(request, 
                                responseHandler, isJsonResponse);
                    };
                request.open("GET", requestUrl, true);
                request.send(null);
            };
        
        function handleResponse (request, responseHandler, isJsonResponse) {
            if ((request.readyState == 4) && (request.status == 200)) {
                if(isJsonResponse == undefined) {
                    isJsonResponse = true;
                }

                if (isJsonResponse) {
                    responseHandler(JSON.parse(request.responseText))
                }

                else {
                    responseHandler(request.responseText);
                }
            };            
        }
        global.$ajaxUtils = ajaxUtils;
    }
)(window);