function FMouse(n1,pic1,n2,pic2) 
{ 	
	if (n1.name != "menu"+chapter+"p") {
		n1.src="/images/"+pic1;
		n2.src="/images/"+pic2;
	}
}

function Preload() 
{ 	
// check if image-maps will work.
  var mo=false;
  browserName = navigator.appName;
  browserVer = parseInt(navigator.appVersion.substring(0,1));
  if ((browserName == "Netscape") && (browserVer >= 3)) { mo = true }
  if ((browserName == "Microsoft Internet Explorer") && (browserVer >= 4)) { mo=true }

// preload images.
if(mo) {
  a11=new Image; a11.src="/images/but1.gif";  
  a12=new Image; a12.src="/images/m1.gif"; 
  a11i=new Image; a11i.src="/images/but1i.gif";  
  a12i=new Image; a12i.src="/images/m1i.gif"; 
  a21=new Image; a21.src="/images/but2.gif";  
  a22=new Image; a22.src="/images/m2.gif"; 
  a21i=new Image; a21i.src="/images/but2i.gif";  
  a22i=new Image; a22i.src="/images/m2i.gif"; 
  a31=new Image; a31.src="/images/but3.gif";  
  a32=new Image; a32.src="/images/m3.gif"; 
  a31i=new Image; a31i.src="/images/but3i.gif";  
  a32i=new Image; a32i.src="/images/m3i.gif"; 
  a41=new Image; a41.src="/images/but4.gif";  
  a42=new Image; a42.src="/images/m4.gif"; 
  a41i=new Image; a41i.src="/images/but4i.gif";  
  a42i=new Image; a42i.src="/images/m4i.gif"; 
  a51=new Image; a51.src="/images/but5.gif";  
  a52=new Image; a52.src="/images/m5.gif"; 
  a51i=new Image; a51i.src="/images/but5i.gif";  
  a52i=new Image; a52i.src="/images/m5i.gif"; 
  a61=new Image; a61.src="/images/but6.gif";  
  a62=new Image; a62.src="/images/m6.gif"; 
  a61i=new Image; a61i.src="/images/but6i.gif";  
  a62i=new Image; a62i.src="/images/m6i.gif"; 
  a71=new Image; a71.src="/images/but7.gif";  
  a72=new Image; a72.src="/images/m7.gif"; 
  a71i=new Image; a71i.src="/images/but7i.gif";  
  a72i=new Image; a72i.src="/images/m7i.gif"; 

 }
}