if (document.images) {            // Active Images
            img1on = new Image();      
            img1on.src = "images/button_01_over.jpg";

            img1off = new Image(); 
            img1off.src = "images/button_01.jpg";
			
			img2on = new Image();      
            img2on.src = "images/button_02_over.jpg";

            img2off = new Image(); 
            img2off.src = "images/button_02.jpg";
			
			img3on = new Image();      
            img3on.src = "images/button_03_over.jpg";

            img3off = new Image(); 
            img3off.src = "images/button_03.jpg";   


			img4on = new Image();      
            img4on.src = "images/mid_06_over.jpg";

            img4off = new Image(); 
            img4off.src = "images/mid_06.jpg";      }

// 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");
        }
}