if (document.images) 
{
	aboutbuttonup       = new Image();
	aboutbuttonup.src   = "../images/about_btn2.jpg" ;
	aboutbuttondown     = new Image() ;
	aboutbuttondown.src = "about_btn1.jpg" ;
}

function buttondown( buttonname )
{
	if (document.images) {
	  if(buttonname == 'aboutbutton') {
	      document[ buttonname ].src = eval( buttonname + "aboutbuttonup.src" );
	  }
	}
}

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