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Creating Applications that Run Efficiently

• To Do List Ordering
• General File Download Practices
• Graphic File Formats
• Cycling Graphics
• Interactive Graphics
• Combining Jamba Applets with Straight HTML

The following subsections describe several suggestions on how you can increase the performance efficiency of your applications.

To Do List Ordering

Keep in mind that the order in which items appear in a To Do List is the order in which actions occur at runtime. As an example, make sure to order the items properly if you want a user to click on a button to display a graphic and then play an audio file. If the audio file downloads faster than the graphic file, you should place the display of the graphic before the playing of the audio. Otherwise, you may find the audio playing well before the graphic appears.

General File Download Practices

Use care in designing your application so that the user does not have to wait too long before information appears.

Displaying A Portion of the Objects Quickly

When your application first appears, you may want to display a small amount of information quickly, just so that the user has something to view right away. For example, an application could display a company logo and a short audio clip that loops while the user waits for the content of the other objects to load.

Pre-Loading Graphics and Audio

If your application uses graphics or audio that will be used later on, you can use a special syntax in the To Do List to pre-load files. Set up the Page object's To Do List so that the Application uses the Load() method to pre-load a specific file. To identify the desired filename, within double quotes, enter the type of file (graphic or audio) followed by a comma, and the filename. The following figure shows an example of how the To Do List would appear when set up to pre-load the files flowers.gif and zoo.au.

Later, when the user clicks on a Push Button to play the audio, the audio file will already be loaded and will play immediately.

Download Messages

By default, when the first page in an application appears, Jamba displays the message "Please wait while files are loading..." If you want to customize this message, you can use the StartupMessage parameter in the . html file. For example, the following line causes the message "Please wait..." to appear instead.

<param name="StartupMessage" value="Please wait...">

Note that if you do not want to display a message at all, use the StartupMessage parameter but do not include any characters between the double quotes that follow value=.

Graphic File Formats

Cycling Graphics

Interactive Graphics

If your application requires several interactive graphics, you might consider using one large graphic with overlaying Hotspot objects instead of several smaller graphics. It is typically faster to download a single graphic that is larger in size, rather than downloading a larger number of smaller graphics.

Combining Jamba Applets with Straight HTML

There are some situations where it may be desirable to use both Jamba-generated objects in conjunction with HTML. Although Jamba objects are rich in functionality, HTML has certain text capabilites and can have a quicker display time. As an example, consider a Web page that is made up of three components. It uses a Jamba-generated Header that contains a cycling graphic and a Push Button that lets the user play an audio file. The mid-section of the page is straight HTML that displays text. The bottom part of the page is a Jamba-generated Footer that contains Forward and Backward Navigation buttons and two Browser objects.

In this example, the Header and Footer are separate applets. Therefore, be aware that they cannot communicate with each other, nor can they affect the HTML text. However, you can set up the Forward and Backward buttons so that each one activates a Browser object to display another HTML page.

In general, consider using straight HTML to display text and graphics if this portion of your Web page does not require the functionality offered by Jamba. For example, if you are familiar with the necessary HTML tags, you can use them to display a graphic in any manner supported by HTML. Remember however, that this means the image will be somewhat limited in its performance. For example, the graphic will not use a special display effect, it will not be able to slide into position, and it will not be able to communicate with any other objects being displayed.

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