if (document.images) {            // Active Images
            img1on = new Image();      
            img1on.src = "http://www.frnservices.com/images/tabs/is-tab-on.gif";
			
			img2on = new Image();      
            img2on.src = "http://www.frnservices.com/images/tabs/as-tab-on.gif";
			
			img3on = new Image();      
            img3on.src = "http://www.frnservices.com/images/tabs/cm-tab-on.gif";
			
			img4on = new Image();      
            img4on.src = "http://www.frnservices.com/images/tabs/os-tab-on.gif";
			
								

			img1off = new Image(); 
            img1off.src = "http://www.frnservices.com/images/tabs/is-tab-off.gif"; 
			
			img2off = new Image(); 
            img2off.src = "http://www.frnservices.com/images/tabs/as-tab-off.gif";  
			
			img3off = new Image(); 
            img3off.src = "http://www.frnservices.com/images/tabs/cm-tab-off.gif"; 
			
			img4off = new Image(); 
            img4off.src = "http://www.frnservices.com/images/tabs/os-tab-off.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");
        }
}