electron/docs/api/web-frame.md
Cheng Zhao c740438032 Rename webFrame.purgeCaches to webFrame.clearCache
This matches the name of session.clearCache.
2016-05-14 22:48:25 +09:00

148 lines
3.6 KiB
Markdown

# webFrame
> Customize the rendering of the current web page.
An example of zooming current page to 200%.
```javascript
const {webFrame} = require('electron');
webFrame.setZoomFactor(2);
```
## Methods
The `webFrame` module has the following methods:
### `webFrame.setZoomFactor(factor)`
* `factor` Number - Zoom factor.
Changes the zoom factor to the specified factor. Zoom factor is
zoom percent divided by 100, so 300% = 3.0.
### `webFrame.getZoomFactor()`
Returns the current zoom factor.
### `webFrame.setZoomLevel(level)`
* `level` Number - Zoom level
Changes the zoom level to the specified level. The original size is 0 and each
increment above or below represents zooming 20% larger or smaller to default
limits of 300% and 50% of original size, respectively.
### `webFrame.getZoomLevel()`
Returns the current zoom level.
### `webFrame.setZoomLevelLimits(minimumLevel, maximumLevel)`
* `minimumLevel` Number
* `maximumLevel` Number
Sets the maximum and minimum zoom level.
### `webFrame.setSpellCheckProvider(language, autoCorrectWord, provider)`
* `language` String
* `autoCorrectWord` Boolean
* `provider` Object
Sets a provider for spell checking in input fields and text areas.
The `provider` must be an object that has a `spellCheck` method that returns
whether the word passed is correctly spelled.
An example of using [node-spellchecker][spellchecker] as provider:
```javascript
webFrame.setSpellCheckProvider('en-US', true, {
spellCheck(text) {
return !(require('spellchecker').isMisspelled(text));
}
});
```
### `webFrame.registerURLSchemeAsSecure(scheme)`
* `scheme` String
Registers the `scheme` as secure scheme.
Secure schemes do not trigger mixed content warnings. For example, `https` and
`data` are secure schemes because they cannot be corrupted by active network
attackers.
### `webFrame.registerURLSchemeAsBypassingCSP(scheme)`
* `scheme` String
Resources will be loaded from this `scheme` regardless of the current page's
Content Security Policy.
### `webFrame.registerURLSchemeAsPrivileged(scheme)`
* `scheme` String
Registers the `scheme` as secure, bypasses content security policy for resources,
allows registering ServiceWorker and supports fetch API.
### `webFrame.insertText(text)`
* `text` String
Inserts `text` to the focused element.
### `webFrame.executeJavaScript(code[, userGesture])`
* `code` String
* `userGesture` Boolean (optional) - Default is `false`.
Evaluates `code` in page.
In the browser window some HTML APIs like `requestFullScreen` can only be
invoked by a gesture from the user. Setting `userGesture` to `true` will remove
this limitation.
### `webFrame.getResourceUsage()`
Returns an object describing usage information of Blink's internal memory
caches.
```javascript
console.log(webFrame.getResourceUsage())
```
This will generate:
```javascript
{
images: {
count: 22,
size: 2549,
liveSize: 2542,
decodedSize: 478,
purgedSize: 0,
purgeableSize: 0
},
cssStyleSheets: { /* same with "images" */ },
xslStyleSheets: { /* same with "images" */ },
fonts: { /* same with "images" */ },
other: { /* same with "images" */ },
}
```
### `webFrame.clearCache()`
Attempts to free memory that is no longer being used (like images from a
previous navigation).
Note that blindly calling this method probably makes Electron slower since it
will have to refill these emptied caches, you should only call it if an event
in your app has occured that makes you think your page is actually using less
memory (i.e. you have navigated from a super heavy page to a mostly empty one,
and intend to stay there).
[spellchecker]: https://github.com/atom/node-spellchecker