Labs/Jetpack/Reboot/JEP/107

JEP 107 - Page Mods

• Champion: Daniel Buchner - daniel@mozilla.com
• Status: Accepted/In-Queue
• Bug Ticket:
• Type: API
• Difficulty: 4

Proposal

Page Mods is chiefly aimed at modifying and manipulating content documents within Firefox. Pages Mods should perform this functionality in a seamless fashion where the end result is the only change visible to the user.

Key Issues

When documents load that are represented in the "matches" white-list, we must ensure that script and styles injected into the page are evaluated by the parser in the normal load cycle. Perhaps we achieve this by dynamically creating resource (or custom protocol) URIs that contain the style and script blocks entered similar to the Background Page mechanisms. These URIs would be dynamically created CSS/JS files that would then be injected in the appropriate places withing the matched documents (CSS files in the doc head, JS files just after the close of the body tag).

Dependencies & Requirements

• Are there any Firefox platform bugs blocking it?
• Does other Jetpack platform code need to be modified or added?
• Does its implementation affect any other projects or code?

API Methods

Page Mods Initialization

var myMods = new pageMod({
    'matches': ['*.google.com', 'jetpack.mozillalabs.com'],
    'includes':{
        'script': ['http://ajax.googleapis.com/ajax/libs/mootools/1.2.4/mootools.js'],
        'styles': ['http://yui.yahooapis.com/3.0.0/build/cssbase/base-min.css']
    },
    'styles': 'body { background: #ffffff; font-family: Trebuchet MS; }' +
              'span.details { font-size: 7px; }'
    },
    'script': function(){
        $('container').addEvents({
            'click:relay(ul li)': function(){ this.setStyles('background','#000') },
            'mousenter:relay(ul li)': function(){ this.tween('background','#000'); },
            'mouseleave:relay(ul li)': function(){ this.tween('background','#fff') }
        });
    }
});

Page Mods Method: add

Arguments:

1. type - (string) The type of modifier being added. Can be 'matches', 'includes', 'styles', or 'script'. If the only argument passed in is an object, Page Mods assumes multiple modifiers will be passed in.
2. data -
   • matches: (array) an array of URL strings
   • includes: (object) 'script' or 'style' keyed nodes whose values are arrays of asset resource strings
   • styles: (string or object) a single string, or an object whose keys are CSS selectors and whose values are objects composed of CSS property keys and values.
   • script: (function) a function that will be injected into the page and called. By default, the function is bound with the target document's window object

Returns:

The Page Mods instance

Notes:

Modifications passed to the Page Mods instance with this method will be added, and persist, on open and future documents matching all of the URL(s) currently on the 'matches' white-list.

Examples:

myMods.add('matches', ['*.digg.com']);

myMods.add('includes', { 
    'script': ['http://ajax.googleapis.com/ajax/libs/mootools/1.2.4/mootools.js'],
    'styles': ['http://yui.yahooapis.com/3.0.0/build/cssbase/base-min.css']
});

// Add styles as an object

    myMods.add('styles', {
        'body':{
            'background': '#ffffff',
            'font-family':'Trebuchet MS'
        },
        'span.details':{
            'font-size':'7px'
        }
    });

// Add styles as a string

    myMods.add('styles', 'a.special { color: green; font-size: 18px; }');

// Creating a function reference

    var pageLog = function(){
        console.log('I just initialized a pageMod!');
     }

// Pass in a function reference or a function wrapped block of script.
// Using a function reference enables removal of the script later
// - see the <i>remove</i> method below for more info.

    myMods.add('script', pageLog);

Page Mods Method: remove

Arguments:

1. type - (string) The type of modifier being added. Can be 'matches', 'includes', 'styles', or 'script'. NOTE: If the only argument is an object, Page Mods assumes multiple modifiers will be passed in.
2. data -
   • matches: expects an array of URL strings
   • includes: expects an array of asset URL strings
   • styles: (object) expects object nodes to be keyed with CSS selectors whose values are arrays of strings for the CSS properties you would like to remove.
   • script: (function reference) removes the script associated to the function reference

Returns:

The attached Page Mods instance

Examples:

myMods.remove('includes', {
    'script': ['http://ajax.googleapis.com/ajax/libs/mootools/1.2.4/mootools.js'],
    'styles': ['http://yui.yahooapis.com/3.0.0/build/cssbase/base-min.css']
});

myMods.remove('styles', {
    'body':['background', 'font-family'],
    'span.details':['font-size']
});

myMods.remove('script', pageLog);

Page Mods Method: empty

Arguments:

1. type - (string) The type of modifier being added. Can be 'matches', 'includes', 'styles', or 'script'. NOTE: If the only argument is an object, Page Mods assumes multiple modifiers will be passed in.
2. data -
   • matches: expects an array of URL strings
   • includes: expects an array of asset URL strings
   • styles: expects a single string, or an object whose keys are CSS selectors and values are objects composed of keys which are CSS properties and their values.
   • script: expects a function, the function is bound with the target document's window object

Returns:

The attached Page Mods instance

Examples:

moddingTwoPages.empty('includes');