if (document.images) 
{  
img21on = new Image ;img21off = new Image;  
img22on = new Image ;img22off = new Image;
img23on = new Image ;img23off = new Image;
img31on = new Image ;img31off = new Image;
img32on = new Image ;img32off = new Image;
img33on = new Image ;img33off = new Image;
img35on = new Image ;img35off = new Image;
img36on = new Image ;img36off = new Image;
img34on = new Image ;img34off = new Image;


img21on.src = "images/but21o.gif";img21off.src = "images/but21.gif"; 
img22on.src = "images/but22o.gif";img22off.src = "images/but22.gif";
img23on.src = "images/but23o.gif";img23off.src = "images/but23.gif"; 
img31on.src = "images/but31o.gif";img31off.src = "images/but31.gif"; 
img32on.src = "images/but32o.gif";img32off.src = "images/but32.gif";
img33on.src = "images/but33o.gif";img33off.src = "images/but33.gif"; 
img35on.src = "images/but35o.gif";img35off.src = "images/but35.gif";
img36on.src = "images/but36o.gif";img36off.src = "images/but36.gif";
img34on.src = "images/but34o.gif";img34off.src = "images/but34.gif"; 


} 
function img_act(imgName) { 
if (document.images) 
{ imgOn = eval (imgName + "on.src"); 
document [imgName].src = imgOn; } } 
function img_inact(imgName) { 
if (document.images) 
{ imgOff = eval(imgName + "off.src"); 
document [imgName].src = imgOff; } }