javascript: context_menu

if (document.addEventListener) {
    document.addEventListener('contextmenu', function(e) {
        alert("You've tried to open context menu"); //here you draw your own menu
        e.preventDefault();
    }, false);
} else {
    document.attachEvent('oncontextmenu', function() {
        alert("You've tried to open context menu");
        window.event.returnValue = false;
    });
}