Firefox 30 for developers
=========================

Want to help document Firefox 30? See the list of bugs that need to be written about and pitch in!

Cambios para los Desarrolladores Web
------------------------------------

### Herramientas para Desarrolladores

* Ha sido implementado el Modelo de Caja Resaltado (Box Model Highlighter) (Error 663778 en Firefox).
* En cualquier parte el nodo DOM aparece en la salida de la consola, se resalta cuando se encima la salida de esa consola (Error 757866 en Firefox). Sucede lo mismo con todas las funciones y objetos JS, son resaltados en la salida de la consola (Error 584733 en Firefox). Más información acerca de las mejoras de la consola pueden econtrarse en el siguiente post del blog.
* Sopoerte para `Console.count()` ha sido agregado (Error 922208 en Firefox).
### CSS

* La propiedad `background-blend-mode` ha sido habilitada por defecto (Error 970600 en Firefox).
* La propiedad no estándar `overflow-clip-box` ha sido implementada para utilizarse solamente en las hojas de estilo UA (Error 966992 en Firefox).
* La propiedad `line-height` afecta ahora a las entradas de lineas de texto sencillas (`<input type=text|password|email|search|tel|url|unknown>` types) aunque no puede reducir su tamaño por debajo de una altura de la línea de `1.0` (Error 349259 en Firefox).
* La propiedad `line-height` ahora también afecta el `type=button`, sin restricciones (Error 697451 en Firefox).
* El cambio al nombre de los keyframes no afecta los elementos actuales (Error 978648 en Firefox).
### HTML

*Sin cambios.*

### JavaScript

* New ES6-compatible array comprehensions (en-US) `[for (item of iterable) item]` and generator comprehensions (en-US) `(for (item of iterable) item)` have been implemented (Error 979865 en Firefox).
* Typed arrays are now extensible and support new named properties (Error 695438 en Firefox).
* The `Error.prototype.stack` (en-US) property now contains column numbers (Error 762556 en Firefox) and has been improved when using `Function()` and `eval()` calls (en-US). This can help you to better debug minified or generated JavaScript code.
* The `Promise.cast()` method has been renamed to `Promise.resolve()` (Error 966348 en Firefox).
### Interfaces/APIs/DOM

* `Navigator.sendBeacon` (en-US) has been implemented, easing telemetry collection (Error 936340 en Firefox).
* Added a `relList` property returning a `DOMTokenList` (en-US) to `HTMLLinkElement` (en-US), `HTMLAreaElement` (en-US) and `HTMLAnchorElement` (Error 968637 en Firefox).
* As per the latest specification, the first argument of `OscillatorNode.start` (en-US) and `OscillatorNode.stop` (en-US) is now optional and defaults to `0` (Error 982541 en Firefox).
* The method `Navigator.requestWakeLock()` and the non-standard `MozWakeLock` are no longer available from the Web on Desktop (Error 963366 en Firefox).
* The `DOM_VK_ENTER` constant has been removed from `KeyboardEvent` (Error 969247 en Firefox).
* Web components' `Document.register` has been adapted to follow the behavior described in the latest version of the specification (Error 856140 en Firefox).
* Basic support for Hit regions on canvas has been added: the methods `CanvasRenderingContext2D.addHitRegion()` and `CanvasRenderingContext2D.removeHitRegion()` have been added. These are disabled by default; to activate them set the preference `canvas.hitregions.enabled` to `true`. (Error 966591 en Firefox)
* The non-standard, and deprecated since Firefox 15, `Blob.mozSlice` is no longer supported (Error 961804 en Firefox).
* The non-standard `ArchiveReader` and `ArchiveRequest` are no longer exposed to the Web (Error 968883 en Firefox).
* WebIDL constructors cannot be called as functions anymore. They need to be preceded by the keyword `new`. (Error 916644 en Firefox)
* Added support for a new value (`alpha`) for the second, optional, parameter of the `Canvas.getContext()` method allowing to define if alpha blending must be stored or not for this context. When not, the per-pixel alpha value in this store is always `1.0`. This allows the back-end to implement a fast-track. (Error 982480 en Firefox)
* `GlobalWorkerScope.consle` now returns for the regular `Console`; `WorkerConsole` (en-US) has been removed (Error 965860 en Firefox).
### MathML

*No change.*

### SVG

* `<feDropShadow>` (en-US), and its interface `SVGFEDropShadowElement` (en-US), from the Filter Effects Module are now supported (Error 964200 en Firefox).
### Audio/Video

* On Linux, Gstreamer 1.0 is now supported (instead of 0.10) (Error 806917 en Firefox).
Security
--------

*No change.*

Changes for add-on and Mozilla developers
-----------------------------------------

* The interface `nsIDOMWindowUtils` now supports the Boolean attribute `audioMuted` and `audioVolume`, a float in the range `[0.0` , `1.0]`, allowing to control the sound produced by a window (that is any tab or iframe). There is no UI for this, but is available to add-ons. (Error 923247 en Firefox)
See also
--------

* Site Compatibility for Firefox 30
### Older versions

* Firefox 29 for developers (en-US)
* Firefox 28 for developers (en-US)
* Firefox 27 for developers (en-US)
* Firefox 26 for developers (en-US)
* Firefox 25 for developers (en-US)
* Firefox 24 for developers (en-US)
* Firefox 23 for developers (en-US)
* Firefox 22 for developers (en-US)
* Firefox 21 for developers (en-US)
* Firefox 20 for developers (en-US)
* Firefox 19 for developers (en-US)
* Firefox 18 for developers (en-US)
* Firefox 17 for developers (en-US)
* Firefox 16 for developers (en-US)
* Firefox 15 for developers (en-US)
* Firefox 14 for developers (en-US)
* Firefox 13 for developers (en-US)
* Firefox 12 for developers (en-US)
* Firefox 11 for developers (en-US)
* Firefox 10 for developers (en-US)
* Firefox 9 for developers
* Firefox 8 for developers (en-US)
* Firefox 7 for developers (en-US)
* Firefox 6 for developers (en-US)
* Firefox 5 for developers (en-US)
* Firefox 4 for developers (en-US)
* Firefox 3.6 for developers (en-US)
* Firefox 3.5 for developers
* Firefox 3 for developers
* Firefox 2 for developers
* Firefox 1.5 for developers