Is refreshing a page in JavaScript the same as posting it back?

[Jason Salas]

Hi everyone,

I've got an interesting problem...is refreshing a page through client-side
JavaScript, specifically:

<script language="JavaScript">
// refreshes the current page every 9 seconds
var intervalID;
intervalID = window.setInterval("nextSlide()",9000);
function nextSlide()
{
document.execCommand("Refresh");
}
</script>

....the same functionally as posting a page back? And if so, is ViewState
not programmatically controllable? I'm thinking perhaps not, because I'm
trying to develop a slide show control that first populates an array, and
then stores a single integer value in ViewState and then increment that
value so that one element within the array is shown at a time:

//1st page load:
int currentSlide = (int)ViewState["nextSlide"];
arrSlide[0] = // display contents;
ViewState["nextSlide"] = currentSlide + 1;

//2nd page load:
int currentSlide = (int)ViewState["nextSlide"];
arrSlide[1] = // display contents;
ViewState["nextSlide"] = currentSlide + 1;

//nth page load:
int currentSlide = (int)ViewState["nextSlide"];
arrSlide[n] = // display contents;
ViewState["nextSlide"] = currentSlide + 1;

The JavaScript above is written to the client page so that that page reloads
automatically, and in theory displays the next slide in the series. But for
some reason, when I refresh the page with the JavaScript, I'm always getting
the first value of ViewState (being 0), so I never advance past the first
slide. This leads me to believe that refreshing the page isn't actually
posting back and not persisting data in ViewState. Got any ideas?

I was thinking that if this is the case (not actually posting back), then
I'll roll a custom event and use the postback interfaces for controls.

Thanks!

Jas

[Phil Weber]

> Is refreshing a page through client-side JavaScript...
> the same functionally as posting a page back?

Jason: No. You need to do a form.post in order to get postback behavior.

Why not pass the desired slide number as a parameter in the querystring?
e.g.:

<script language="JavaScript">
// refreshes the current page every 9 seconds
var intervalID;
intervalID = window.setInterval("nextSlide()", 9000);
function nextSlide()
{
currentSlide += 1;
window.location.href = "http://www.url.com?slide=" +
currentSlide;
}
</script>

--
Phil Weber

[Jason Salas]

Nice! I didn't think of that...I was trying to do it all from the ASP.NET
code. Actually, I did come up with a custom event process of
incrementing/decrementing through the collection, but it requires the user
to manually click through the photos, and I'd rather have it work
automatically.

Thanks for the tip!


"Phil Weber" <philweber@hotmail.com> wrote in message
news:3ea38157$1@tnews.web.devx.com...
> > Is refreshing a page through client-side JavaScript...
> > the same functionally as posting a page back?
>
> Jason: No. You need to do a form.post in order to get postback behavior.
>
> Why not pass the desired slide number as a parameter in the querystring?
> e.g.:
>
> <script language="JavaScript">
> // refreshes the current page every 9 seconds
> var intervalID;
> intervalID = window.setInterval("nextSlide()", 9000);
> function nextSlide()
> {
> currentSlide += 1;
> window.location.href = "http://www.url.com?slide=" +
> currentSlide;
> }
> </script>
>
> --
> Phil Weber
>