To bring Buttons down according to the page length.

Hi Friends,

I have a travel form with a Submit button and a Cancel button at the Bottom centre of the page after all the textbox fields to enter the data.I need to give an option so that these 2 buttons can come down according to the length of the page.should i put these buttons in a div and use css.I am not an expert in writing css codes.Can someone help me with this...please.

Thanks.