Using JavaScript Behaviors

Macromedia Dreamweaver 8 behaviors place JavaScript code in documents to allow visitors to interact with a web page to change the page in various ways, or to cause certain tasks to be performed. A behavior is a combination of an event with an action triggered by that event. In the Behaviors panel, you add a behavior to a page by specifying an action and then specifying the event that triggers that action.

Events are, effectively, messages generated by browsers indicating that a visitor to your page has done something. For example, when a visitor moves the pointer over a link, the browser generates an onMouseOver event for that link; the browser then checks to see whether there’s some JavaScript code (specified in the page being viewed) that the browser is supposed to call when that event is generated for that link. Different events are defined for different page elements; for example, in most browsers onMouseOver and onClick are events associated with links, whereas onLoad is an event associated with images and with the body section of the document.

An action consists of pre-written JavaScript code that performs a specific task, such as opening a browser window, showing or hiding a layer, playing a sound, or stopping a Macromedia Shockwave movie. The actions provided with Dreamweaver are carefully written by Dreamweaver engineers to provide maximum cross-browser compatibility.

After you attach a behavior to a page element, whenever the event you’ve specified occurs for that element, the browser calls the action (the JavaScript code) that you’ve associated with that event. (The events that you can use to trigger a given action vary from browser to browser.) For example, if you attach the Popup Message action to a link and specify that it will be triggered by the onMouseOver event, then whenever someone points to that link with the mouse pointer in the browser, your message pops up in a dialog box.

A single event can trigger several different actions, and you can specify the order in which those actions occur.

Dreamweaver provides about two dozen behavior actions; additional actions can be found on the Macromedia Exchange website as well as on third-party developer sites. (See Downloading and installing third-party behaviors.) You can write your own behavior actions if you are proficient in JavaScript. For more information on writing behavior actions, see Extending Dreamweaver (Help > Extending Dreamweaver).

This chapter contains the following sections:

Using the Behaviors panel

About events

Applying a behavior

Attaching a behavior to text

Changing a behavior

Updating a behavior

Creating new actions

Downloading and installing third-party behaviors

Using the behavior actions that come with Dreamweaver