// Swap image
function SwapImg($n) {
 var presrc = document.getElementById($n).src;
 document.getElementById($n).src=presrc.replace(/.gif/,"_sw.gif");
 return false;
}

// Restore image
function RestImg($n) {
 var presrc = document.getElementById($n).src;
 document.getElementById($n).src=presrc.replace(/_sw.gif/,".gif");
 return false;
}