Actually, the button is not clicked on the website, is it?

The button is clicked by the user in their browser, isn't it?

The browser contains an HTTP Client and, when the user clicks in the browser, it uses its HTTP Client to make an HTTP Request to the HTTP Server in your web "site"

The HTTP Server in your web "site" will pass this request to some other part of your web "site" (its "brains") - and that's what needs to control the download to your embedded device.


To do this, your embedded kit must be an HTTP Client, so it must be talking to an HTTP Server in your web "site" - in principle at least, this is a different HTTP Server from the one talking to your user's browser.

Something like this:

                                    Web "Site"
                       ...................................                
                      :                                   :
+--------+            +-------+     +--------+     +------+            +--------+
|        |            |       |     |        |     |      |            |        |
|Embedded|  internet  | HTTP  |     |        |     | HTTP |  internet  |User's  |
| Kit    +<---------->+Server +<--->+ Brains +<--->+Server+<---------->|Browser |
|        |            |(kit)  |     |        |     |(user)|            |        |
|        |            |       |     |        |     |      |            |        |
+--------+            +-------+     +--------+     +------+            +--------+
                      :                                   :
                       ...................................

This means that your web "site" cannot initiate contact with the embedded kit: there is no way for an HTTP Server to send anything unsolicited to a Client - that is the very nature of the Client-Server architecture!

Take another look at the Polling approach described by Craig:
http://www.8052.com/forum/read.phtml?id=151765