Get keyboard modifier when user click in toolbar command of safari extension

I want to get keyboard modifiers (like shift or option keys) when user click by toobar command of my safari extension.

In global HTML page I have next code:

safari.application.addEventListener("command", performCommand, false);

function performCommand(event)
{
    if (event.command === "foo") {

          //TODO: is shift pressed?
    }
}

Is it possible? O开发者_开发问答r may be exists any workaround?

Unfortunately, keyCode is not currently available on the command and validate events for toolbar items. I submit enhancement request to apple.

In Safari, you should be able to do:

if (event.shiftKey) {
  // Shift key was pressed...
}