Really big forms?

We have an administrative application that allows users to select multiple line items from a scrollable area. When the form is submitted, an integer identifier is posted for each line item.

We are experiencing difficulty with the form if the user individually selects over about 100 rows or so. Selecting 1 or more rows up to a small bunch works perfectly. Is this a server configuration error, Form problem, html problem or php problem? Nothing seems to work.

This may seem obvious, but are you using GET or POST in the form method? If you are using GET you do know you are limited in the amount of data that can be passed?

We've used the POST method in this case. Is there some limit to the amount of data you can send with a POST? Is there some additional work required to work with posted data? From what I know, post is really a file transfer command and sends large data in blocks. The additional benefit is that it does not display the arguments as part of the URL.

Now, is there some additional work I need to be doing to pull down the now potentially very large selection from the list object in my form.

In this case, the object may contain thousands of rows and the user may legitimately want to select and send a thousand or more keys from the selection with this form. My understanding was that Post would break up the form data and PHP would reassemble the data on the other end and handle everything exactly as if it had been a small data set sent with GET method. What am I overlooking? PHP docs are no help and this situation seems to arise infrequently enough that it is not addressed in articles here or at WebMonkey.

Theoretically, there isn't a limit. It could be the browser you are using. I've never heard of this problem tho.