Question

I am attempting to create asp.net elements on the fly using javascript. I can successfully create html elements on the fly like so

var _upload = document.createElement("input");

_upload.setAttribute("type", "file");

_upload.setAttribute("ID", "upload" + rownum);

_upload.setAttribute("runat", "server");

_upload.setAttribute("name", "uploads" + rownum);

A few questions:

1. Is this the equivalent to the asp.net FileUpload control?

2. How can I create the exact asp.net controls in javascript?

What can an asp.net fileupload do that my control I created above cannot do if anything?

Answer 1

Florians idea is useful, but (depending on your case of course) there may be an even simpler fix: create the fileupload control when rendering the page but put in inside a hidden div. Then all you have to do in JavaScript is show the div.

Some example code (asp.net controls may be wrong, it’s been a while since I used them):

mypage.aspx:

<div id="fileupload-div">
   <FileUpload id="myupload" runat="server" />
</div>
<button id="mybutton">Show upload control</button>

style.css

#fileupload-div { display: none }

mypage.js

$("#mybutton").click(function() {
    $("#fileupload-div").show();
});