Detect if a character or number has been typed

Question

I would like to set up a home page where pressing any character (lowercase or uppercase) or any number redirects the user to the login page, as the home page itself doesn't have anything to do that requires typing.

My first attempt was this:

document.onkeyup = function() {
  document.location.href = "/login"
}

This works but it works for every key, including cursors, tab, and even caps lock. How can I restrict this function so it only responds to characters and numbers?

Answer 1

When the event occurs, the key code is sent as an event argument. We can use that to determine if a character or number key was pressed. Like this:

document.onkeyup = function(e) {

  if ((e.keyCode >= 65 && e.keyCode <= 90) ||
      (e.keyCode >= 97 && e.keyCode <= 122) ||
      (e.keyCode >= 48 && e.keyCode <= 57)){
      document.location.href = "/login";
  }
};

For reference, the number used above are ASCII codes, you can find the complete list here: http://asciitable.com/. 48-57 are numbers 0-9, 65-90 are upper case characters, and 97-122 are lower case characters.

You can find a very simple JS Fiddle example here: http://jsfiddle.net/jpYyg/ . Remember to click inside the "Result" panel (bottom-right one) before pressing any buttons or it won't work!

HTH