function switchiPhoneImage(currentElName, action){
    var currentEl = $(currentElName);
    var leftNevEl = $("leftNev");
    var rightNevEl = $("rightNev");
    var imgEl = $("iphone");
    
    var current=1;
    if (currentEl){
        current = currentEl.getValue();
        current = parseInt (current);
    }
        
    var currentImgClass = "PhoneImg" + current; 
    var nextImgClass;
    
    if (current == 1 && action == 'prev')
        return;
    if (current == 8 && action == 'next')
        return;
    
    if (action == 'next'){
        current = current + 1
        currentEl.value = current;
        nextImgClass = "PhoneImg" +  current;
        imgEl.removeClassName(currentImgClass);
        imgEl.addClassName(nextImgClass);
        
        if (current == 8){
            rightNevEl.removeClassName("RightNevEnabled");
            rightNevEl.addClassName("RightNev");
        }
        if (current > 1){
            leftNevEl.removeClassName("LeftNev");
            leftNevEl.addClassName("LeftNevEnabled");
        }
        
        
        
    } else if (action == 'prev'){
        current = current - 1;
        currentEl.value = current;
        nextImgClass = "PhoneImg" +  current;
        imgEl.removeClassName(currentImgClass);
        imgEl.addClassName(nextImgClass);
        
        if (current == 1){
            leftNevEl.removeClassName("LeftNevEnabled");
            leftNevEl.addClassName("LeftNev");
        }
        if (current < 8){
            rightNevEl.removeClassName("RightNev");
            rightNevEl.addClassName("RightNevEnabled");
        }
        
        
    }
}