if (document.images) {            
            but1on = new Image();      
            but1on.src = "/_Image/serv_serv_over.gif"; 
            but2on = new Image(); 
            but2on.src = "/_Image/serv_prod_over.gif";  
            
            

            but1off = new Image(); 
            but1off.src = "/_Image/serv_serv.gif"; 
            but2off = new Image();          
            but2off.src = "/_Image/serv_prod.gif"; 
           
            
        }


function butOn(imgName) {
        if (document.images) {
            document[butName].src = eval(butName + "on.src");
        }
}


function imgOff(butName) {
        if (document.images) {
            document[butName].src = eval(butName + "off.src");
        }
}