Writing Javascript

As we have learned while creating “Hello, world!” addon, Javascript part of addon is given in separate .js file and looks like:

This is a typical structure of Javascript part - let’s learn how it works.

Addon initialization

.js file should contain single top-level function - in our example it is named init, but it can have any other or no name at all. It is run when addon is applied to target page.

This function creates and enclosures all the addon logic but does not launch it yet. In our example, single function doWork is defined. Instead, it returns an object (addonEntry in our example) that contains another function in its field start.

Addon launch

The start function actually launches the addon - in our example it calls doWork.

Arguments of start function:

• taistApi is an object that provides access to all Taist features. All the features are described in other chapters of this guide. In doWork we see use of log function - it’s a preferred way of Debug output.
• entryPoint is used for fine-tuning of what addon parts to launch on what pages of target site.