Helper function for loading JSONP

jsonp.js

var jsonp = function(url)
{
    var script = window.document.createElement('script');
    script.async = true;
    script.src = url;
    script.onerror = function()
    {
        alert('Can not access JSONP file.')
    };
    var done = false;
    script.onload = script.onreadystatechange = function()
    {
        if (!done && (!this.readyState || this.readyState === 'loaded' || this.readyState === 'complete'))
        {
            done = true;
            script.onload = script.onreadystatechange = null;
            if (script.parentNode)
            {
                return script.parentNode.removeChild(script);
            }
        }
    };
    window.document.getElementsByTagName('head')[0].appendChild(script);
};