loadURL = function loadURL(url, callback) {
    var xhr = new XMLHttpRequest();
    xhr.onreadystatechange = function onreadystatechange() {
        if (this.readyState === 4) {
            if (callback) callback(this.responseText);
        }
    };
    xhr.open('GET', url);
    xhr.send();
}
Load a URL and return its contents in a callback.

@method loadURL
@memberof Utilities

@param {String} url URL of object
@param {Function} callback callback to dispatch with content

@return {undefined} undefined