if (document.images) {
				
												home_btnup       = new Image();
												home_btnup.src   = "graphics/home_btn.gif" ;
												home_btndown     = new Image() ;
												home_btndown.src = "graphics/home_btn_hover.gif" ;						
												
												about_btnup       = new Image();
												about_btnup.src   = "graphics/about_btn.gif" ;
												about_btndown     = new Image() ;
												about_btndown.src = "graphics/about_btn_hover.gif" ;				
											
												portfolio_btnup  = new Image();
												portfolio_btnup.src   = "graphics/portfolio_btn.gif" ;
												portfolio_btndown     = new Image() ;
												portfolio_btndown.src = "graphics/portfolio_btn_hover.gif" ;
							
													contact_btnup       = new Image();
													contact_btnup.src   = "graphics/contact_btn.gif" ;
													contact_btndown     = new Image() ;
													contact_btndown.src = "graphics/contact_btn_hover.gif" ;

			
}
function buttondown( buttonname )
{
    if (document.images) {
      document[ buttonname ].src = eval( buttonname + "down.src" );
    }
}
function buttonup ( buttonname )
{
    if (document.images) {
      document[ buttonname ].src = eval( buttonname + "up.src" );
    }
}