I created before triggers with the following basic skeleton for each table that I wanted to add the range constraint to.
if NEW.columnname > theupperrange then
SELECT `**columnname is out of range**` from thetable into @str_val;
This will cause the insert to fail with the follow error message
Unknown column `**columnname is out of range**`
//req is the name of the XMLHttpRequest object i create to handle interaction between
msg = req.responseText
arr_msg = msg.split("**")
themsg = arr_msg
//window1 is where data is entered, I know it's a real meaningful name:)
regular application stuff
The idea of how to write the trigger was not original with me. I got it from http://www.brokenbuild.com/blog/category/mysql/ , who I believe said he got it from another source.