JavaScript

Inherits: Object

Singleton that connects the engine with the browser’s JavaScript context in HTML5 export.

Description

The JavaScript singleton is implemented only in the HTML5 export. It’s used to access the browser’s JavaScript context. This allows interaction with embedding pages or calling third-party JavaScript APIs.

Note: This singleton can be disabled at build-time to improve security. By default, the JavaScript singleton is enabled. Official export templates also have the JavaScript singleton enabled. See Compiling for the Web in the documentation for more information.

Tutorials

• #calling-javascript-from-script in Exporting for the Web

Methods

Signals

• pwa_update_available ( )

Emitted when an update for this progressive web app has been detected but is waiting to be activated because a previous version is active. See pwa_update to force the update to take place immediately.

Method Descriptions

• JavaScriptObject create_callback ( Object object, String method )

Creates a reference to a script function that can be used as a callback by JavaScript. The reference must be kept until the callback happens, or it won’t be called at all. See JavaScriptObject for usage.

• Variant create_object ( String object, … ) vararg

Creates a new JavaScript object using the new constructor. The object must a valid property of the JavaScript window. See JavaScriptObject for usage.

• void download_buffer ( PoolByteArray buffer, String name, String mime=”application/octet-stream” )

Prompts the user to download a file containing the specified buffer. The file will have the given name and mime type.

Note: The browser may override the MIME type provided based on the file name‘s extension.

Note: Browsers might block the download if download_buffer is not being called from a user interaction (e.g. button click).

Note: Browsers might ask the user for permission or block the download if multiple download requests are made in a quick succession.

• Variant eval ( String code, bool use_global_execution_context=false )

Execute the string code as JavaScript code within the browser window. This is a call to the actual global JavaScript function eval().

If use_global_execution_context is true, the code will be evaluated in the global execution context. Otherwise, it is evaluated in the execution context of a function within the engine’s runtime environment.

• JavaScriptObject get_interface ( String interface )

Returns an interface to a JavaScript object that can be used by scripts. The interface must be a valid property of the JavaScript window. The callback must accept a single Array argument, which will contain the JavaScript arguments. See JavaScriptObject for usage.

• bool pwa_needs_update ( ) const

Returns true if a new version of the progressive web app is waiting to be activated.

Note: Only relevant when exported as a Progressive Web App.

• Error pwa_update ( )

Performs the live update of the progressive web app. Forcing the new version to be installed and the page to be reloaded.

Note: Your application will be reloaded in all browser tabs.

Note: Only relevant when exported as a Progressive Web App and pwa_needs_update returns true.