Use a hidden iframe to send data. Useful for bypassing cross-origin request restrictions where you don't need to know the response, just to send the data.

sendData.js

/**
 * Send data to a URL using a hidden iframe
 * @param  {String} URL    The URL to send to
 * @param  {Object} data   An object describing the data to send (optional)
 * @param  {String} method The method (GET / POST) (optional)
 */
function sendData(URL, data, method){
    /* Check we have a URL to send to */
    if (typeof URL != "string"){
        return;
    }
    /* Create a hidden iframe to use to submit the data */
    var iframe = document.createElement("iframe");
    iframe.setAttribute("style", "display: none");
    iframe.setAttribute("name", "iframe-da39a3ee-5e6b4b0d-3255bfef-95601890-afd80709");
    /* Create a hidden form to set our data in */
    var form = document.createElement("form");
    form.setAttribute("action", URL);
    form.setAttribute("method", typeof method == "undefined" ? "GET" : method);
    form.setAttribute("style", "display: none");
    form.setAttribute("target", "iframe-da39a3ee-5e6b4b0d-3255bfef-95601890-afd80709");
    document.body.appendChild(form);
    /* Create hidden inputs for our data */
    for (var key in data){
        var input = document.createElement("input");
        input.setAttribute("name", key);
        input.setAttribute("value", data[key]);
        form.appendChild(input);
    }
    /* Submit it! */
    form.submit();
}
/**
 * Example use:
 *
 * sendData("http://www.google.com", {"foo": "bar"}, "GET");
 */