Question

I have a page with a form that has a file upload input item targeted to a hidden iframe. When the form is posted to the iframe the server processes the file and returns a json object. I’m not sure how to use jquery, or plain old javascript for that matter, to listen for the returned object. I have some code set up for my iframe such as…

$("#upload_target").load(function () {
   //what to do here - how do I get the json object?
});

Does anyone know how to wire up jquery to listen for the json object that’s sent back to the iframe? Thanks.

Answer 1

I finally figured out how to do it….

$("#upload_target").load(function (data) {
    if (data != null){
        var obj = jQuery.parseJSON(data);
        //...work with obj here.
    }
});

Whether it’s the right way or not, it works.

edit – actually I got a bit ahead of myself. here’s the correct code….

$("#upload_target").load(function (){
        var retval = $(frames['upload_target'].document).text();
        if (retval != null)
        {
            try{
                var obj = jQuery.parseJSON(retval);
                //...work with obj here.
            }catch(err){}
        }
});

One thing I had to also change was making sure that my MVC controller action was setting the JSONResult.ContentType = “text/plain”. Otherwise I was getting a save as download dialog.