if (document.images) {
// Active Images
    imghearstcoc_1on = new Image();                       
    imghearstcoc_1on.src = "images/navigation/welcome-yellow-f.gif";  
    imghearstcoc_2on = new Image();                       
    imghearstcoc_2on.src = "images/navigation/welcome-yellow-e.gif";  
    imghearstcoc_3on = new Image();                       
    imghearstcoc_3on.src = "images/navigation/welcome-red-f.gif";  
    imghearstcoc_4on = new Image();                       
    imghearstcoc_4on.src = "images/navigation/welcome-red-e.gif";  

// Inactive Images
    imghearstcoc_1off = new Image();                       
    imghearstcoc_1off.src = "images/navigation/welcome-black-f.gif";  
    imghearstcoc_2off = new Image();                       
    imghearstcoc_2off.src = "images/navigation/welcome-black-e.gif";   
    imghearstcoc_3off = new Image();                       
    imghearstcoc_3off.src = "images/navigation/welcome-yellow2-f.gif";  
    imghearstcoc_4off = new Image();                       
    imghearstcoc_4off.src = "images/navigation/welcome-yellow2-e.gif";   
}

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

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