document.onkeyup = function(e) {
if (e.which == 77) {
alert("M key was pressed");
} else if (e.ctrlKey && e.which == 66) {
alert("Ctrl + B shortcut combination was pressed");
} else if (e.ctrlKey && e.altKey && e.which == 89) {
alert("Ctrl + Alt + Y shortcut combination was pressed");
} else if (e.ctrlKey && e.altKey && e.shiftKey && e.which == 85) {
alert("Ctrl + Alt + Shift + U shortcut combination was pressed");
}
};