if (document.images) {            // Active Images

            img1on = new Image();      

            img1on.src = "/images/tool_about01.gif"; 

			img2on = new Image();

            img2on.src = "/images/tool_courses01.gif"; 
		
			img3on = new Image();

            img3on.src = "/images/tool_lecturer01.gif";
			 
			img4on = new Image();

            img4on.src = "/images/tool_contact01.gif";
			
			
        
						

            img1off = new Image(); 

            img1off.src = "/images/tool_about0.gif"; 
			
			img2off = new Image(); 

            img2off.src = "/images/tool_courses0.gif"; 

            img3off = new Image();

            img3off.src = "/images/tool_lecturer0.gif";
			 
			img4off = new Image();

            img4off.src = "/images/tool_contact0.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");

        }

}