Labs/Jetpack/Reboot/JEP/108

JEP 108 - Background Pages

• Champion: Daniel Buchner - daniel@mozilla.com
• Status: Accepted/In-Queue
• Bug Ticket:
• Type: API

Proposal

Background Pages are like a more open and free sandbox for doing most anything in a traditional web page with a DOM context, but with a key difference: the page is augmented with escalated, waterfall chrome privileges. It is essentially along the same line of a Web Worker, just more open and accessible.

Key Issues

Ensure script and styles injected into the page is evaluated by the parser in the normal load cycle. Perhaps we achieve this by dynamically creating resource URIs that take the styles and script blocks entered via the Background Page API methods and dynamically create css/js files out of them for injection in the appropriate places (CSS files in the doc head, JS files just after the close of the body tag)

Dependencies & Requirements

• We must be able to give the code in the top window of this page chrome privileges that are strictly one-way/descending in nature.
• Dynamically generated code sent to the Background Page should be injected and executed in the Background Page's window context.

Internal Methods

• TBD

API Methods

$Moz.background({ interval: 10000, bind:jetpack.tabs[0] }, function(){
    return window.document;
});

• Background Page work units are bound with the Background Page's window object by default
• If interval option is present, the function is wrapped with setInterval(); and the $Moz.background method returns the interval timer so that it may be cleared outside of the Background Page.
• Functional context for the function passed to the background page can be passed as an option