if (document.images) {
    // Active Images
            b1on = new Image();          
            b1on.src = dir+"img/b1_on.gif";       
            b2on = new Image();          
            b2on.src = dir+"img/b2_on.gif";       
            b3on = new Image();          
            b3on.src = dir+"img/b3_on.gif";       

//            b4on = new Image();          
//            b4on.src = dir+"img/b4_on.gif";       
//            b5on = new Image();          
//            b5on.src = dir+"img/b5_on.gif";       
//            b6on = new Image();          
//            b6on.src = dir+"img/b6_on.gif";       
           
     // Inactive Images
            b1off = new Image();          
            b1off.src = dir+"img/b1.gif";       
            b2off = new Image();          
            b2off.src = dir+"img/b2.gif";       
            b3off = new Image();          
            b3off.src = dir+"img/b3.gif";       
//            b4off = new Image();          
//            b4off.src = dir+"img/b4.gif";       
//            b5off = new Image();          
//            b5off.src = dir+"img/b5.gif";       
//            b6off = new Image();          
//            b6off.src = dir+"img/b6.gif";       


    for(var ii=1;ii<7;ii++)
       {
       bon[ii] = new Image();          
       bon[ii].src = "img/b"+ii+"_on.gif";       
       boff[ii] = new Image();          
       boff[ii].src = "img/b"+ii+".gif";       
      }



   }

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

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