javascript - Simulating "focus" and "blur" in jQuery .live() method

Question

Update: As of jQuery 1.4, $.live() now supports focusin and focusout events.

---

jQuery currently¹ doesn't support "blur" or "focus" as arguments for the $.live() method. What type of work-around could I implement to achieve the following:

$("textarea")
  .live("focus", function() { foo = "bar"; })
  .live("blur",  function() { foo = "fizz"; });

^{1. 07/29/2009, version 1.3.2}

Answer 1

Working solution:

(function(){

    var special = jQuery.event.special,
        uid1 = 'D' + (+new Date()),
        uid2 = 'D' + (+new Date() + 1);

    jQuery.event.special.focus = {
        setup: function() {
            var _self = this,
                handler = function(e) {
                    e = jQuery.event.fix(e);
                    e.type = 'focus';
                    if (_self === document) {
                        jQuery.event.handle.call(_self, e);
                    }
                };

            jQuery(this).data(uid1, handler);

            if (_self === document) {
                /* Must be live() */
                if (_self.addEventListener) {
                    _self.addEventListener('focus', handler, true);
                } else {
                    _self.attachEvent('onfocusin', handler);
                }
            } else {
                return false;
            }

        },
        teardown: function() {
            var handler = jQuery(this).data(uid1);
            if (this === document) {
                if (this.removeEventListener) {
                    this.removeEventListener('focus', handler, true);
                } else {
                    this.detachEvent('onfocusin', handler);
                }
            }
        }
    };

    jQuery.event.special.blur = {
        setup: function() {
            var _self = this,
                handler = function(e) {
                    e = jQuery.event.fix(e);
                    e.type = 'blur';
                    if (_self === document) {
                        jQuery.event.handle.call(_self, e);
                    }
                };

            jQuery(this).data(uid2, handler);

            if (_self === document) {
                /* Must be live() */
                if (_self.addEventListener) {
                    _self.addEventListener('blur', handler, true);
                } else {
                    _self.attachEvent('onfocusout', handler);
                }
            } else {
                return false;
            }

        },
        teardown: function() {
            var handler = jQuery(this).data(uid2);
            if (this === document) {
                if (this.removeEventListener) {
                    this.removeEventListener('blur', handler, true);
                } else {
                    this.detachEvent('onfocusout', handler);
                }
            }
        }
    };

})();

Tested in IE/FF/Chrome. Should work exactly as you intended.

UPDATE: Teardowns now work.