how to transfer textbox value from .net page to html page textbox?

[Steve]

My question is both .net and javascript and I thought it would be best
posted here.

I have a pop up html page (it just has to be html) with a textbox and a
button next to it. When the user clicks on the button an asp.net page
pops up which allows the user to upload a photo. The asp.net code then
puts the url of this photo into a textbox in the asp.net page. I now
want to be able to press a button and have the value from the asp.net
textbox transferred to the html textbox. Can you please show me how
with example code? I assume the code has to be in javascript?

I hope that's clear. I know you may be thinking why don't I do the
whole thing in .net but the html page has just loads of other things
and javascript on it and I can't really change it.

Thank you.

[RobG]

Steve wrote:

My question is both .net and javascript and I thought it would be best
posted here.

I have a pop up html page (it just has to be html) with a textbox and a
button next to it. When the user clicks on the button an asp.net page
Once it leaves the server, it is HTML. ASP .NET is irrelevant after that.

pops up which allows the user to upload a photo. The asp.net code then
puts the url of this photo into a textbox in the asp.net page. I now
want to be able to press a button and have the value from the asp.net
textbox transferred to the html textbox. Can you please show me how
ASP is on the server, I guess you mean in the browser page.
with example code? I assume the code has to be in javascript?

<script type="text/javascript">

function writeText(id, txt)
{
var s;
if ( document.createTextNode
&& document.getElementById
&& (s = document.getElementById(id)) ){
while (s.firstChild) s.removeChild(s.firstChild);
s.appendChild(document.createTextNode(txt));
}
}

</script>

<form action="">
<input type="file" id="fileName">
<input type="button" value="Show file path"
onclick="writeText('thePath', this.form.fileName.value);">
</form>
<div>Here is the filename and path: <span id="thePath"></span></div>
[...]
--
Rob

[Steve]

Thank you for the replies Rob and Lee. I will try out the suggestions.
Thank you for taking the time to point me in the right direction.

[Steve]

Thank you for your help guys, I got that bit to work.