Send Data To Different Domain

I need to send a fairly small amount of data (~215characters) from Domain A to Domain B using only JavaScript (No JQuery, etc). I have full control over Domain B, so how the data gets there really isn't as important as how it's sent (Only using JavaScript) and there is zero need for Domain B to send anything back开发者_运维问答 to Domain A.

I believe one solution to this problem is having Domain A request an image file with a query string from Domain B. On Domain B I can then capture the request and parse the data in the query string. In fact, I believe this is how analytics works.

Possible other solutions?

Image is not ideal as modern browsers might block it as part of privacy, think I saw it somewhere.

Personally I will create a form on the fly and submit it to hidden frame:

var _TargetPage = "http://www.domainB.com/page.php";

function SendData(strData) {
    var oFrame = document.getElementById("HiddenFrame");
    if (!oFrame) {
        oFrame = document.createElement("iframe");
        oFrame.id = "HiddenFrame";
        oFrame.name = "HiddenFrame";
        oFrame.style.display = "none";
        document.body.appendChild(oFrame);
    }

    var oForm = document.getElementById("HiddenForm");
    if (!oForm) {
        oForm = document.createElement("form");
        oForm.id = "HiddenForm";
        oForm.method = "POST";
        oForm.action = _TargetPage;
        oForm.target = "HiddenFrame";
        document.body.appendChild(oForm);

        var oInput = document.createElement("input");
        oInput.type = "hidden";
        oInput.name = "HiddenInput";
        oForm.appendChild(oInput);
    }

    oForm.elements["HiddenInput"].value = strData;
    oForm.submit();
}

This way you don't have to mess with URL encoding and you have more control over things, plus it's harder to spoof. (Browsing to certain URL alone won't be enough)