function isEventSupported(eventName, element) {

    element = element || document.createElement(TAGNAMES[eventName] || 'div');
    eventName = 'on' + eventName;
    
    var isSupported = (eventName in element);
    
    if (!isSupported) {
      // if it has no `setAttribute` (i.e. doesn't implement Node interface), try generic element
      if (!element.setAttribute) {
        element = document.createElement('div');
      }
      if (element.setAttribute && element.removeAttribute) {
        element.setAttribute(eventName, '');
        isSupported = typeof element[eventName] == 'function';

        // if property was created, "remove it" (by setting value to `undefined`)
        if (typeof element[eventName] != 'undefined') {
          element[eventName] = undef;
        }
        element.removeAttribute(eventName);
      }
    }
    
    element = null;
    return isSupported;
  }

Mouse events:

Key events:

HTML events

View events

Form events:

Form controls' events:

Activation events:

MSHTML DOM events:

Unexistent (most likely) events:

Unexistent in Opera <=10a

iPhone touch/gesture events

HTML5 events

Proprietary