Alert message error - need help

Question

I'm very poor in the javascript department when developping PDFs and I would need a little help with this issue.
On one row, I would need field C to check on exit if Field A is larger than field C. If field A is not larger, then I need an alert message to pop up and say "Field C cannot be larger than field A." and then the cursor would return to field C, and the value of field C would become 0 (zero).
I've tried a few ways, but I do not seem to be getting it right. Any one have a clue how to do this effectively?
Thank you!

Answer 1

It would appear that there isn't. The sample I posted worked for me, which makes me think there are other factors involved such as:
1. What version of compatibility are you saving the form as? (I saved it as compatible with 8.1 or later)
2. What program is being used to open the pdf? (I used Acrobat 8.1.6)
3. Is the user actually clicking the button with the mouse or simply hitting the Enter key to answer the pop-up? (I clicked it)
4. Machine OS (I'm using 64-bit XP, Service Pack 2)
Something else is going on that is making the pdf perform differently, maybe something as simple as the form moving outside the environment it was created in. No matter what the reason is, controlling the focus is the issue and it doesn't look to be something we can control reliably.