Cancel the keydown in HTML.

Question

Hello,

How can I cancel the keydown of a specific key on the keyboard, for example(space, enter and arrows) in an HTML page.

Thanks

Answer 1

Catch the keydown event and return false. It should be in the lines of:

<script>
document.onkeydown = function(e){
  var n = (window.Event) ? e.which : e.keyCode;
  if(n==38 || n==40) return false;
}
</script>

(seen here)

The keycodes are defined here

edit: update my answer to work in IE

Answer 2

Hi,

jQuery has a nice KeyPress function which allows you to detect a key press, then it should be just a case of detecting the keyvalue and performing an if for the ones you want to ignore.

edit: for example:

$('#target').keypress(function(event) {
  if (event.keyCode == '13') {
     return false; // or event.preventDefault();
  }
});

Answer 3

Just return false. Beware that on Opera this doesn't work. You might want to use onkeyup instead and check the last entered character and deal with it. Or better of use JQuery KeyPress

Answer 4

If you're only interested in the example keys you mentioned, the keydown event will do, except for Opera, where you'll need to cancel the keypress event. It's much easier to reliably identify non-printable keys in the keydown event than the keypress event, so the following uses a variable to set in the keydown handler to tell the keypress handler whether or not to suppress the default behaviour.

var cancelKeypress = false;

document.onkeydown = function(evt) {
    evt = evt || window.event;
    cancelKeypress = /^(13|32|37|38|39|40)$/.test("" + evt.keyCode);
    if (cancelKeypress) {
        return false;
    }
};

/* For Opera */
document.onkeypress = function(evt) {
    if (cancelKeypress) {
        return false;
    }
};