Numeric Data Input

Working on a form to input numeric data.  I am using <cfform> and the <cfinput> tags.   To help the user with data entry issues I want to show the user the comma format when their data entry goes beyond 3 digits.  This should be simple but I can't get this to work.   What is correct way to make this happen?   On the SQL end it's going into either a DECIMAL(10.2) or an INT.  

Thanks!