electron/docs/api/web-frame.md

webFrame

Customize the rendering of the current web page.

Process: Renderer

An example of zooming current page to 200%.

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 Number - 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 Number - The current zoom level.

webFrame.setZoomLevelLimits(minimumLevel, maximumLevel)

• minimumLevel Number
• maximumLevel Number

Deprecated: Call setVisualZoomLevelLimits instead to set the visual zoom level limits. This method will be removed in Electron 2.0.

webFrame.setVisualZoomLevelLimits(minimumLevel, maximumLevel)

• minimumLevel Number
• maximumLevel Number

Sets the maximum and minimum pinch-to-zoom level.

webFrame.setLayoutZoomLevelLimits(minimumLevel, maximumLevel)

• minimumLevel Number
• maximumLevel Number

Sets the maximum and minimum layout-based (i.e. non-visual) zoom level.

webFrame.setSpellCheckProvider(language, autoCorrectWord, provider)

• language String
• autoCorrectWord Boolean
• provider Object
  • spellCheck Function - Returns Boolean.
    • text String

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 as provider:

const {webFrame} = require('electron')
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[, options])

• scheme String
• options Object (optional)
  • secure Boolean (optional) - Default true.
  • bypassCSP Boolean (optional) - Default true.
  • allowServiceWorkers Boolean (optional) - Default true.
  • supportFetchAPI Boolean (optional) - Default true.
  • corsEnabled Boolean (optional) - Default true.

Registers the scheme as secure, bypasses content security policy for resources, allows registering ServiceWorker and supports fetch API.

Specify an option with the value of false to omit it from the registration. An example of registering a privileged scheme, without bypassing Content Security Policy:

const {webFrame} = require('electron')
webFrame.registerURLSchemeAsPrivileged('foo', { bypassCSP: false })

webFrame.insertText(text)

• text String

Inserts text to the focused element.

webFrame.executeJavaScript(code[, userGesture, callback])

• code String
• userGesture Boolean (optional) - Default is false.
• callback Function (optional) - Called after script has been executed.
  • result Any

Returns Promise - A promise that resolves with the result of the executed code or is rejected if the result of the code is a rejected promise.

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 Object:

• images MemoryUsageDetails
• cssStyleSheets MemoryUsageDetails
• xslStyleSheets MemoryUsageDetails
• fonts MemoryUsageDetails
• other MemoryUsageDetails

Returns an object describing usage information of Blink's internal memory caches.

const {webFrame} = require('electron')
console.log(webFrame.getResourceUsage())

This will generate:

{
  images: {
    count: 22,
    size: 2549,
    liveSize: 2542
  },
  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 occurred 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).