Capturing a double keystroke with jQuery

double_keystroke.js

// Will fire an alert if user presses the "F" key twice within 300 miliseconds
var dblCtrlKey = 0;
$(document).keydown(function(e) {
  if (dblCtrlKey != 0 && e.which == 70) {
    alert("Ok double F");
  } else {
    dblCtrlKey = setTimeout('dblCtrlKey = 0;', 300);
  }
});