Max values for number input.

Hi

I have just purchased this plug in because I wanted to set maximum input values in a number input field. I have, for example set max value of 800… then I was able to enter a value of 900 and was not stopped from processing the product through to check out. I had no warning using Chrome and in Firefox the input box was highlighted in red but both still allowed to be processed. Is there a way I can put a hard stop and throw up the error message I have completed.

Thanks

Jim…