Description:

A very simple chrome extension that allows the user to translate text selected in the browser into Spanish without opening a new tab.

Installation:

Chrome -> tools -> extensions -> load unpacked extension.

Some notes on the flow of execution

We set up an actionListener with a response function as a parameter.

The page loads

getPageInfo(onPageInfo) is called, where onPageInfo is a function. It is the callback function.

onPageInfo is added to the stack for later use.

Chrome tabs API is used to inject content_script.js into the current webpage.

content_script.js creates an object which contains info about the current webpage. It sends a request to the chrome extension with this info.

When the extension receives the request, the actionListener is triggered. When the actionListener was defined, it was given a function as an argument, and that function took a single argument. Now the actionListener has been triggered by a request, containing the page information JSON. This page information JSON is the argument of the function and that function is now called.

When the function is called, the first callback is taken off the stack

• in our case this is the onPageInfo function.

onPageInfo is called with the JSON parameter and it populates the "fromText" field with the page information. whew!