[RESOLVED] Why is this simple code not working?

[HowTo]

ok i had a look at this:
http://www.webdevelopersjournal.com/...jsevents2.html

now i am confused about this bit of code for the reset button:

function reset()
    {
    document.getElementById('TextBox1').value=""
    document.getElementById('TextBox2').value=""
    return false;
    }

if i dont Set the UsesubmitBehaviour=False for the button ; then why there is a postback after resetting the textbox?

please please help