JEP 108 - Background Page
- Champion: Daniel Buchner - daniel@mozilla.com
- Status: Under Review
- Bug Ticket: 546740
- 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.
Use-Cases
1. Google Maps API Data If you wanted to utilize the data available via Google Maps API, you would need to instantiate the API's script within the context of a DOM. This is due to Google Maps reliance on the elements and script it pulls in to make data fetching possible. I might want to have a Jetpack that searches the page for addresses and business titles allowing the user to mouseover those items and view geolocalized details about such places in a tooltip.
2. Native Type Proxy & DOM-Reliant Script Execution Environment It is almost a certainty that developers will want to use their js library of choice to interact with web content. To enable this more easily, they could use this JEP's DOM as a Native Type proxy and as the primary location to instantiate their DOM dependent code.
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
Background Page Global: $dom
Background Page Method: run
Description:
Allows you to run code in the DOM Worker's window context
Arguments:
- options - (object)
- bind: (mixed) a variable that will be bound as the 'this' keyword in the function
- arguments: (array) an array of mixed variables passed as the function arguments
- timeout: (number) a number that is used to set the timeout duration
- interval: (number) a number that is used to set the interval duration
- action - (function) a function to be executed within the DOM of the Background Page - by default, the Background Page's window object is the bound 'this' within the function
Returns:
user defined return value - The function's return value as specified by the user
or
If timeout or interval options are used:
array - an array whose first item is the function's user defined return value, and second is a variable the user can save to clear the timing event
Notes:
Examples:
$dom.run({ interval: 10000 }, function(){
return window.location;
});
Background Page Method: empty
Arguments:
This method takes no arguments
Returns:
The Background Page Global object: $dom
Examples:
$dom.empty();
Background Page Method: reset
Arguments:
No arguments are used in accordance with this method
Returns:
The Background Page Global object: $dom
Examples:
$dom.reset();