Overview

Using Dreamweaver, you can easily add a variety of content to web pages. Add assets and design elements, such as text, images, colors, movies, sound, and other forms of media. Using the Asset panel allows you to easily organize the assets in a site; you can then drag most assets directly from the Assets panel into a Dreamweaver document. JavaScript behaviours may be applied to various objects and events to allow users to interact with the web pages of your site.

Library Items

You can create a library item from any element in the body section of a document, including text, tables, forms, Java applets, plug-ins, ActiveX elements, navigation bars, and images.

For linked items such as images, the library stores only a reference to the item. The original file must remain at the specified location for the library item to work correctly. It can still be useful to store an image in a library item, though; for example, you could store a complete img tag in a library item, which would allow you to easily change the image's alt text, or even its src attribute, throughout the site. (Don't use this technique to change an image's width and height attributes, though, unless you also use an image editor to change the actual size of the image.)

To create a library item:

1. Select a portion of a document to save as a library item.
2. Do one of the following:
• Choose Window > Library and drag the selection into the Library category of the Assets panel.
• Click the New Library Item button at the bottom of the Assets panel (in the Library category).
• Choose Modify > Library > Add Object to Library.
3. Enter a name for the new library item.

Each library item is saved as a separate file (with the file extension .lbi) in the Library folder of the site's local root folder.

Using JavaScript Behaviors

Dreamweaver 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.

Note: Behavior code is client-side JavaScript code; that is, it runs in browsers, not on servers.

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 prewritten JavaScript code that performs a specific task, such as opening a browser window, showing or hiding a layer, playing a sound, or stopping a Shockwave movie. The actions provided with Macromedia Dreamweaver MX 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 MX provides about two dozen behavior actions; additional actions can be found on the Macromedia Exchange website as well as on third-party developer sites. You can write your own behavior actions if you are proficient in JavaScript.

Note: The terms behavior and action are Dreamweaver terms, not HTML terms. From the browser's point of view, an action is just like any other piece of JavaScript code.