[javascript] How to disable right-click context-menu in JavaScript

I have used this:

document.onkeydown = keyboardDown;
document.onkeyup = keyboardUp;
document.oncontextmenu = function(e){
 var evt = new Object({keyCode:93});
 stopEvent(e);
 keyboardUp(evt);
}
function stopEvent(event){
 if(event.preventDefault != undefined)
  event.preventDefault();
 if(event.stopPropagation != undefined)
  event.stopPropagation();
}
function keyboardDown(e){
 ...
}
function keyboardUp(e){
 ...
}

Then I catch e.keyCode property in those two last functions - if e.keyCode == 93, I know that the user either released the right mouse button or pressed/released the Context Menu key.

Hope it helps.