This module defines the dojo.connect API. This modules also provides keyboard event handling helpers. This module exports an extension event for emulating Firefox's keypress handling. However, this extension event exists primarily for backwards compatibility and is not recommended. WebKit and IE uses an alternate keypress handling (only firing for printable characters, to distinguish from keydown events), and most consider the WebKit/IE behavior more desirable.
See the dojo/_base/connect reference documentation for more information.
| Parameter | Type | Description |
|---|---|---|
| object | undefined | |
| listener | undefined |
dojo.connect is a deprecated event handling and delegation method in
Dojo. It allows one function to "listen in" on the execution of
any other, triggering the second whenever the first is called. Many
listeners may be attached to a function, and source functions may
be either regular function calls or DOM events.
Connects listeners to actions, so that after event fires, a listener is called with the same arguments passed to the original function.
Since dojo.connect allows the source of events to be either a
"regular" JavaScript function or a DOM event, it provides a uniform
interface for listening to all the types of events that an
application is likely to deal with though a single, unified
interface. DOM programmers may want to think of it as
"addEventListener for everything and anything".
When setting up a connection, the event parameter must be a
string that is the name of the method/event to be listened for. If
obj is null, kernel.global is assumed, meaning that connections
to global methods are supported but also that you may inadvertently
connect to a global by passing an incorrect object name or invalid
reference.
dojo.connect generally is forgiving. If you pass the name of a
function or method that does not yet exist on obj, connect will
not fail, but will instead set up a stub method. Similarly, null
arguments may simply be omitted such that fewer than 4 arguments
may be required to set up a connection See the examples for details.
The return value is a handle that is needed to
remove this connection with dojo.disconnect.
| Parameter | Type | Description |
|---|---|---|
| obj | Object |
Optional The source object for the event function.
Defaults to |
| event | String | String name of the event function in obj.
I.e. identifies a property |
| context | Object | null | The object that method will receive as "this". If context is null and method is a function, then method inherits the context of event. If method is a string then context must be the source object object for method (context[method]). If context is null, kernel.global is used. |
| method | String | Function | A function reference, or name of a function in context. The function identified by method fires after event does. method receives the same arguments as the event. See context argument comments for information on method's scope. |
| dontFix | Boolean |
Optional If obj is a DOM node, set dontFix to true to prevent delegation of this connection to the DOM event manager. |
When obj.onchange(), do ui.update():
dojo.connect(obj, "onchange", ui, "update"); dojo.connect(obj, "onchange", ui, ui.update); // same
Using return value for disconnect:
var link = dojo.connect(obj, "onchange", ui, "update"); ... dojo.disconnect(link);
When onglobalevent executes, watcher.handler is invoked:
dojo.connect(null, "onglobalevent", watcher, "handler");
When ob.onCustomEvent executes, customEventHandler is invoked:
dojo.connect(ob, "onCustomEvent", null, "customEventHandler"); dojo.connect(ob, "onCustomEvent", "customEventHandler"); // same
When ob.onCustomEvent executes, customEventHandler is invoked with the same scope (this):
dojo.connect(ob, "onCustomEvent", null, customEventHandler); dojo.connect(ob, "onCustomEvent", customEventHandler); // same
When globalEvent executes, globalHandler is invoked with the same scope (this):
dojo.connect(null, "globalEvent", null, globalHandler);
dojo.connect("globalEvent", globalHandler); // same
Ensure that every time obj.event() is called, a message is published on the topic. Returns a handle which can be passed to dojo.disconnect() to disable subsequent automatic publication on the topic.
| Parameter | Type | Description |
|---|---|---|
| topic | String | The name of the topic to publish. |
| obj | Object |
Optional The source object for the event function. Defaults to kernel.global if null. |
| event | String | The name of the event function in obj. I.e. identifies a property obj[event]. |
dojo.connectPublisher("/ajax/start", dojo, "xhrGet");
Remove a link created by dojo.connect.
Removes the connection between event and the method referenced by handle.
| Parameter | Type | Description |
|---|---|---|
| handle | Handle | the return value of the dojo.connect call that created the connection. |
Checks an event for the copy key (meta on Mac, and ctrl anywhere else)
| Parameter | Type | Description |
|---|---|---|
| e | Event | Event object to examine |
Invoke all listener method subscribed to topic.
| Parameter | Type | Description |
|---|---|---|
| topic | String | The name of the topic to publish. |
| args | Array |
Optional An array of arguments. The arguments will be applied to each topic subscriber (as first class parameters, via apply). |
dojo.subscribe("alerts", null, function(caption, message){ alert(caption + "\n" + message); };
dojo.publish("alerts", [ "read this", "hello world" ]);
Attach a listener to a named topic. The listener function is invoked whenever the named topic is published (see: dojo.publish). Returns a handle which is needed to unsubscribe this listener.
| Parameter | Type | Description |
|---|---|---|
| topic | String | The topic to which to subscribe. |
| context | Object |
Optional Scope in which method will be invoked, or null for default scope. |
| method | String | Function | The name of a function in context, or a function reference. This is the function that is invoked when topic is published. |
dojo.subscribe("alerts", null, function(caption, message){ alert(caption + "\n" + message); });
dojo.publish("alerts", [ "read this", "hello world" ]);
Remove a topic listener.
| Parameter | Type | Description |
|---|---|---|
| handle | Handle | The handle returned from a call to subscribe. |
var alerter = dojo.subscribe("alerts", null, function(caption, message){ alert(caption + "\n" + message); };
...
dojo.unsubscribe(alerter);