Events.js

Events = (function( $ ) {

  // Store each registered $.Callbacks object by namespace
  var cache = {},
      slice = [].slice;

  return {
    // Bind callback to event
    bind : function( ev, callback, options ) {
    
      // Make $.Callbacks default to having stopOnFalse
      options = options || 'stopOnFalse';
      
    
      // If this callback list does not exist, create it
      if ( !cache[ ev ] ) {
        cache[ ev ] = {
          cb    : $.Callbacks( options ),
          funcs : []
        }
      }
      
      // Add callback to $.Callbacks
      cache[ ev ].cb.add( callback );
      
      cache[ ev ].funcs.push( callback );
    
     
    }, // bind
    
    updateOptions : function( ev, options ) {
    
      var inc, len, func;
    
      // Ignore update if it didn't exist
      if ( !cache[ ev ] ) {
        return;
      }
      
      // Remove all callbacks from $.Callbacks
      cache[ev].cb.empty();
      
      // Create a new $.Callbacks list with the new options
      cache[ ev ].cb = $.Callbacks( options );
      
      // Get size of callback functions already added
      len = cache[ ev ].funcs.length;
      
      // Loop through array of callback functions to insert into fresh $.Callbacks
      for ( inc = 0; inc < len; ++inc ) {
      
        func = cache[ ev ].funcs[ inc ];
      
        cache[ ev ].cb.add( func );
      
      } // for inc
    
    }, // updateOptions

    unbind : function( ev, callback ) {
    
      // Ignore unbind if it didn't exist
      if ( !cache[ ev ] ) {
        return;
      }
      
      // Remove from list
      cache[ ev ].cb.remove( callback );
      
      // Remove from cache of funcs for option change
      cache[ ev ].funcs = $.grep( cache[ ev ].funcs, function(value) {
        return value !== callback;
      });
      
    }, // unbind

    trigger : function( ev ) {
    
      // Ignore trigger if it doesn't exist
      if ( !cache[ ev ] ) {
        return;
      }
    
      // Get dynamic number of arguments, knowing first argument is always event
      var args = slice.call( arguments ),
          pass = args.splice(1);
          
      // Call $.Callbacks fire method with right arguments
      cache[ ev ].cb.fireWith( null, pass );
      
    } // trigger
    
  } // return

})( jQuery ); // Events

test.js

var a = function() {
  console.log('a');
  return false;
};

var b= function() {
  console.log('b');
};

Events.bind( 'foo', a );
Events.bind( 'foo', b );

// Logs a
Events.trigger( 'foo' );

Events.updateOptions( 'foo', '' );

// Logs a then b
Events.trigger( 'foo' );

Events.updateOptions( 'foo', 'stopOnFalse' );

// Logs a
Events.trigger( 'foo' );

Events.unbind( 'foo', a );

// Logs b
Events.trigger( 'foo' );