Adobe Extending Dreamweaver CS4 - Manual (Page 241)

235 EXTENDING DREAMWEAVER CS4
Behaviors
4 Dreamweaver displays a dialog box that contains the BODY elements of the Action file. If the Action file’s body tag
contains an onLoad handler, Dreamweaver executes it.
5 The user fills in the parameters for the action. Dreamweaver executes event handlers that are associated with the
form fields as the user encounters them.
6 The user clicks OK.
7 Dreamweaver calls the behaviorFunction() and applyBehavior() functions in the selected Action file. These
functions return strings that are inserted into the user’s document.
8 If the user later double-clicks the action in the Actions column, Dreamweaver reopens the Parameters dialog box
and executes the
onLoad handler. Dreamweaver then calls the inspectBehavior() function in the selected Action
file, which fills in the fields with the data that the user previously entered.
Inserting multiple functions in the user’s file
Actions can insert multiple functions—the main behavior function plus any number of helper functions—into the
head section. Two or more behaviors can even share helper functions as long as the function definition is exactly the
same in each Action file. One way of ensuring that shared functions are identical is to store each helper function in an
external JavaScript file and insert it into the appropriate Action files using
<SCRIPT SRC="externalFile.js"> .
When the user deletes a behavior, Dreamweaver attempts to remove any unused helper functions that are associated
with the behavior. If other behaviors are using a helper function, it is not deleted. Because the algorithm for deleting
helper functions errs on the side of caution, Dreamweaver might occasionally leave an unused function in the user’s
document.
Handling actions that require return value
Sometimes an event handler must have a return value (for example, onMouseOver="window.status='This is a
link'; return true" ). But if Dreamweaver inserts the "return behaviorName(args)" action into the event
handler, behaviors later in the list are skipped.
To get around this limitation, set the document.MM_returnValue variable to the desired return value within the string
that the behaviorFunction() function returns. This setting causes Dreamweaver to insert return
document.MM_returnValue at the end of the list of actions in the event handler. For an example that uses the
MM_returnValue variable, see the Validate Form.js file in the Configuration/Behaviors/Actions folder within the
Dreamweaver application folder.
A simple behavior example
To understand how behaviors work and how you can create one, it’s helpful to look at an example. The
Configuration/Behaviors/Actions folder inside the Dreamweaver application folder contains examples; however,
many are very complex. This example is simpler so that you can learn about creating behaviors. Start with the simple
Action file Call JavaScript.htm (along with its counterpart, Call JavaScript.js, which contains all the JavaScript
functions).
To create the behavior, you create an extension, create the HTML files to browse, and test the behavior.