Restrict the user to wnter only 1000 part numbers

[sheela.vikramkumar]

I have a requirment where the user should not be allowed to enter more than 1000 partnumbers in a textbox prompt. or it should show an alert when he tries to enter more than 1000 part numbers.

[blom0344]

You're actually going to ask a user to select - by hand - up to 1000 selections in a textbox (why exactly 1000 anyway) ?  Is this a hoax?  :o

Surely partnumbers are related to some sort of category/ies, so you can use pre-selects aka cascading prompts?