I want to use struts validation,when field is invalidate,my program can raise information,like follows: Username is required. Password is required. Phone Number is required. I know it's server-side validation,I want to use client-side validation,so I put some code in my JSP files: When I run this JSP and put some invalidation in fields,I find Javascript don't work at all,it still raise follows: Username is required. Password is required. Phone Number is required. My JDK is 1.6,tomcat5.5.17 and struts is 1.2.9,I want to know if struts is 1.2.9 change the method of supporting client-side validation? Any idea will be appreciated!