function resizeFrame(f) {
  f.style.height = f.contentWindow.document.body.scrollHeight + "px";
}

function HoverImgOf(filename)
{
   var re = new RegExp("(.+)\\.(gif|png|jpg)", "g");
   return filename.replace(re, "$1_hover.$2");
}
function NormalImgOf(filename)
{
   var re = new RegExp("(.+)_hover\\.(gif|png|jpg)", "g");
   return filename.replace(re, "$1.$2");
}