Class Ext.Toolbar.Button

• scope : Object

  The scope in which to execute the handler function. The handler function's "this" context.

• delay : Number

  The number of milliseconds to delay the invocation of the handler after the event fires.

• single : Boolean

  True to add a handler to handle just the next firing of the event, and then remove itself.

• buffer {Number} Causes the handler to be scheduled to run in an Ext.util.DelayedTask delayed by the specified number of milliseconds. If the event fires again within that time, the original handler is not invoked, but the new handler is scheduled in its place.

Combining Options
Using the options argument, it is possible to combine different types of listeners:

A normalized, delayed, one-time listener that auto stops the event and passes a custom argument (forumId)

el.on('click', this.onClick, this, {
    single: true,
    delay: 100,
    forumId: 4
});

Attaching multiple handlers in 1 call
The method also allows for a single argument to be passed which is a config object containing properties which specify multiple handlers.

foo.on({
    'click' : {
        fn: this.onClick,
        scope: this,
        delay: 100
    },
    'mouseover' : {
        fn: this.onMouseOver,
        scope: this
    },
    'mouseout' : {
        fn: this.onMouseOut,
        scope: this
    }
});

Or a shorthand syntax:

foo.on({
    'click' : this.onClick,
    'mouseover' : this.onMouseOver,
    'mouseout' : this.onMouseOut,
     scope: this
});