// Right-click protection based on code by Dave Lauderdale, published at: www.digi-dl.com

// update this message to customize the behavior
var message = "This image is protected by copyright laws. \n"
              + "Please contact the National Postal Museum \n"
              + "to obtain image use permission.";

function stop_right_click_IE(e) {
    if (navigator.appName == "Microsoft Internet Explorer")
    {
        if (event.button == "2" || event.button == "3") {
            var stop_click = true;
            if ((event && event.srcElement) && !event.srcElement.src) {
                stop_click = false;
            }

            if (stop_click) {
                document.oncontextmenu = disable_context_menu;
                alert(message);
                return false;
            } else {
                document.oncontextmenu = enable_context_menu;
                return true;
            }
        }
    }
}

function stop_right_click_NS(event) {
    if ((document.layers || (document.getElementById && !document.all)))
    {
        if (event.which == "2" || event.which == "3") {
            var stop_click = true;

            if ((event && event.target) && !event.target.src) {
                stop_click = false;
            }

            if (stop_click) {
                document.oncontextmenu = disable_context_menu;
                alert(message);
                return false;
            } else {
                document.oncontextmenu = enable_context_menu;
                return true;
            }
        }
    }
}

function disable_context_menu() { return false; }
function enable_context_menu()  { return true; }
document.onmousedown = stop_right_click_IE;
document.onmouseup = stop_right_click_NS;
document.oncontextmenu = disable_context_menu;