Asynchronous cross-domain POST request via JavaScript?

Question

I could just create a form and use that to do a POST request to any site, thing is the FORM method isn't asynchronous, I need to know when the page has finished loading. I tried messing around with this using an iframe with a form inside, but no success.

Any ideas?

EDIT

unfortunately I have no control over the response data, it varies from XML, json to simple text.

Answer 1

You can capture the onload event of an iframe. Target your form to the iframe and listen for the onload. You will not be able to access the contents of the iframe though, just the event.

Try something like this:

<iframe id='RS' name='RS' src='about:blank' onload='loaded()'></iframe>

<form action='wherever.php' target='RS' method='POST'>...</form>

script block:

var loadComplete = 0
function loaded() {
    //avoid first onload
    if(loadComplete==0) {
        loadComplete=1
        return()
    }
    alert("form has loaded")
}

Answer 2

IF you want to make cross domain requests you should either made a JSON call or use a serverside proxy. A serverside proxy is easy to set up, not sure why people avoid it so much. Set up rules in it so people can not use the proxy to request other things.