Abstraction of XHR written as part of Udacity's HTML5 Game course. Kinda neat.

Abstract XHR

function xhrGet(reqUri, callback, type) {
    var caller = this.caller;
    
    var xhr = new XMLHttpRequest();
    
    xhr.open("GET", reqUri, true);
    
    if(type){
        xhr.responseType = type;
    }
    
    xhr.onload = function(){
        if(callback){
            try {
                callback(xhr);
            } catch(e) {
                throw "xhrGet failed: \n" + reqUri + "\n Exception: " + e + "\n Response text: " + xhr.responseText + "\n Caller: " + caller;
            }
        }
    };
        
    
    xhr.send();
}

parseJSON = function (xhr) {
    var parsedJSON = JSON.parse(xhr.responseText);

    var x = parsedJSON['frames']['chaingun_impact.png']['spriteSourceSize']['x'];
    console.log(x);
    return x;
};

playSound = function (xhr) {
    try {
        var context = new webkitAudioContext();

        var mainNode = context.createGainNode(0);
        mainNode.connect(context.destination);

        var clip = context.createBufferSource();

        context.decodeAudioData(xhr.response, function (buffer) {
            clip.buffer = buffer;
            clip.gain.value = 1.0;
            clip.connect(mainNode);
            clip.loop = true;
            clip.noteOn(0);
        }, function (data) {});
    }
    catch(e) {
        console.warn('Web Audio API is not supported in this browser');
    }
};