var base = "images/layout/";

if (document.images) {           
  img1on = new Image();   img1on.src = base + "menu_home_on.gif"; 
  img1off = new Image();  img1off.src = base + "menu_home_off.gif";  
  img2on = new Image();   img2on.src = base + "menu_techniques_on.gif"; 
  img2off = new Image();  img2off.src = base + "menu_techniques_off.gif";  
  img3on = new Image();   img3on.src = base + "menu_gallery_on.gif"; 
  img3off = new Image();  img3off.src = base + "menu_gallery_off.gif";  
}

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

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

function popup(url, name, width, height) {
  settings="toolbar=no,location=no,directories=no,"+"status=no,menubar=no,scrollbars=no,"+"resizable=no,width="+width+",height="+height;

  MyNewWindow=window.open(url,name,settings);
}