Ajax AsyncFileUpload Using a different control to trigger the browse button click

Hello,

I'm trying to create a custom control. (with Ajax and some jquery js)

The control has a custom styled button that is visible and a AsyncFileUpload control that is not (transparent).

When the user clicks the styled button, it triggers the browse button on the AsyncFileUpload control.

Does anyone know what the AsyncFileUpload trigger is called?

So the styled button { onclick="browse()"}  and the function is 

        function browse() {            $('#imageUploadBrowse').trigger('click');        }

But the trigger of the <input type="file" is click, what is the tigger for the AsyncFileUpload?

<div><ajaxToolkit:AsyncFileUpload ID="imageUploadBrowse" runat="server" CssClass="InputFileUpload FileUploadPosition"/><%--<input name="imageUpload" type="file" id="imageUploadBrowse" style="position:absolute; top:-100px;"/>--%><input type="button" value="browse files" onclick="browse()"/></div>