function na_change_img_src(name, nsdoc, rpath, preload)
{ 
var img = eval((navigator.appName.indexOf('Netscape', 0) != -1) ? nsdoc+'.'+name : 'document.all.'+name);
if (name == '')
return;
if (img) {
img.altsrc = img.src;
img.src = rpath;
} 
} 

function na_restore_img_src(name, nsdoc)
{
var img = eval((navigator.appName.indexOf('Netscape', 0) != -1) ? nsdoc+'.'+name : 'document.all.'+name);
if (name == '')
return;
if (img && img.altsrc) {
img.src = img.altsrc;
img.altsrc = null;
} 
}