Using Dreamweaver To Add JavaScript To Your Web Pages
JavaScript is a well-established scripting language which creates code that can execute both an HTML page loads and after it has loaded. It is very efficient since it can run independently on the computers of the visitors to your web site. Thus freeing up your server to do other things. It is so widely used on web sites that, though it is possible for a user to disable JavaScript within their browser settings, most people will need to leave it active if they are to interact with the sites they visit. Adobe Dreamweaver allows web developers to add JavaScript to their pages by using what it refers to as “behaviors”.
A Dreamweaver behavior is an automatically generated JavaScript function which is activated by a given user or browser action. To use behaviors, choose Window > Behaviors. Before attaching a behavior, you must highlight one of the elements on your page such as a hyperlink or image. Then you need to choose a behavior by clicking on the plus sign in the top left of the Behaviors window.
You will also need to ensure that the correct event (click, double-click etc.) is linked to the behavior. Dreamweaver will always assign an event automatically. However, if this event is not the one you actually want, just select a different event by clicking on the drop-down menu located to the right of the name of the event in the Behaviors panel.
Dreamweaver’s behaviors fall into four main categories: manipulation of images, alerts and windows, form field handling and CSS handling. To get a feel for how behaviors work, let’s take an example of a behavior in each of these categories.
There was a time when almost every website featured the rollover effect on its navigation buttons. With the development of CSS, this is no longer the case. However, the facility of having an image change appearance when the mouse passes over it is still useful. Dreamweaver achieves this effect with the “Swap Image” behavior which can either be added to an image or can be created automatically by inserting a rollover image (Insert > Image Objects > Rollover Image) rather than a static one.
In the alerts and windows category, we have Dreamweaver’s “Open Browser Window” behavior. This creates the ever-popular pop-up window. When you assign the behavior, Dreamweaver asks you to choose the HTML page you would like displayed in the window as well as the attributes you would like to add or suppress, such as scroll bars or the ability to resize the window.
The most important and useful form-handling behavior is “Validate Form”. This can be triggered either on submission of the form (”onSubmit”) or when a given text field loses focus (”onBlur”). When you assign the behavior, you choose the type of validation you wish to perform: ensuring that the field has not been left blank, contains a valid email address, contains a number or contains a number between two specific values.
Dreamweaver has a number of behaviors which can be applied manipulate the CSS attributes associated with a given page element. One such behavior is Show/Hide Elements. This enables you to make the content of an HTML element visible or hidden based on an action performed by the user. You can apply this behavior to the content of an H1, DIV, P(aragraph) basically, any element that can contain stuff.
Naturally, there is some overhead involved in using Dreamweaver’s behavior in terms of the code generated within your web page. To make your pages accessible and search engine friendly, it is recommended that you transfer JavaScript code into an external .js file and then link each of your web pages to the external JavaScript file. In Dreamweaver’s code view, highlight all of the JavaScript code between the opening and closing SCRIPT tags, then choose Cut from the Edit menu. Create an empty text file, paste in all the code and save the file with a .js file extension. Finally, in the opening SCRIPT tag on your web page type src=”myscript.js”, replacing “myscript” with the name of your file.
Tags: Software
