how to validate upload file size limit?

Hi all,
I need to set a maximum file size upload in my form, so that users can't upload file larger than 30MB.
Actually the php.ini allow 100MB files.
But I can't find a way to set this limit using data assist.
I can specify file extensions but not file size.
Is there a way to do this?
TIA
tony

You can use server validation and validate the file size attribute from the upload using number validation.

Originally Said By: Ray Borduin

  You can use server validation and validate the file size attribute from the upload using number validation.  

Is this correct?

1- 2016-09-06 09_05_40-Server Validations_ file size.png
2- 2016-09-06 09_05_40-Server Validations_ file size number validation.png

What format number should I choose?
TIA
tony

That should work. US format should be fine. I don't think it will actually matter since no commas or decimals will be in the number anyway.

Originally Said By: HBak82161085

  That should work. US format should be fine. I don't think it will actually matter since no commas or decimals will be in the number anyway.  

Thanks for the reply.
But how can I set a size limit of 20MB?
Should I set Maximum to 20480000 (20 480 000)?

I tried everything with different format (english, european, international) but it always fail validation.

In the panel bindings there is another series of server values:
example:
uploads/[FileName]: File Size
... where "uploads" should be my upload folder.

What can I do whit these values? Should I use them instead of the first ones (se my attachment above)?

Sorry for all these questions but unfortunately I'm in a hurry.

Thanks Again for your help.

tony

Ok, after an heavy trial-and-error session, I found the solution.
I was using the wrong value from the binding panel.
Now I used the "file size" that you find below the form field (not the one under "upload file (my_field)").
I set a limit using the international format and set it to 5120000 to limit file size to 5MB.
Now it works.
Thanks to all for the help.
Just a note of disappointment for the online help system. I can't find any reference to all the bindings value created by the WA extensions related to file upload.