ASP File upload control

Question

I am using dynamic ajax file upload control. AjaxControlToolkit.AsyncFileUpload()

While i am trying to upload file, in page load the value of Request.ServerVariables["QUERY_STRING"] is, "AsyncFileUploadID=MainContent_flbFileUpload1&rnd=01846502097323537".

Can anyone tell me, why this happens?

Answer 1

In AsyncFileUpload.pre.js file found in ajaxcontroltoolkit.zip and in _onload: function (e) { .... } has below sample lines which create the resulting postback URL as:

mainForm.action = url + 'AsyncFileUploadID=' + this.get_element().id + '&rnd=' 
                  + Math.random().toString().replace(/\./g, "");

mainForm.target = this._iframeName;