The Firefox and Safari browsers both display the behaviour of a scrollbar “pushing” a web page 15 pixels to the left. This causes a messy look and feel on centered websites when page A has no scrollbars and page B does. The web site will shift left and right due to scrollbar displacement.

To overcome this use the following CSS code:

     /*this is to keep page from shifting to left on load in safari and firefox*/
html { min-height: 100%; margin-bottom: 1px; }
html { overflow: -moz-scrollbars-vertical !important; }