Singleton that connects the engine with the browser's JavaScript context in HTML5 export.
</brief_description>
<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.
[b]Note:[/b] 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 [url=$DOCS_URL/development/compiling/compiling_for_web.html]Compiling for the Web[/url] in the documentation for more information.
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.
Creates a new JavaScript object using the [code]new[/code] constructor. The [code]object[/code] must a valid property of the JavaScript [code]window[/code]. See [JavaScriptObject] for usage.
Prompts the user to download a file containing the specified [code]buffer[/code]. The file will have the given [code]name[/code] and [code]mime[/code] type.
[b]Note:[/b] The browser may override the [url=https://en.wikipedia.org/wiki/Media_type]MIME type[/url] provided based on the file [code]name[/code]'s extension.
[b]Note:[/b] Browsers might block the download if [method download_buffer] is not being called from a user interaction (e.g. button click).
[b]Note:[/b] Browsers might ask the user for permission or block the download if multiple download requests are made in a quick succession.
Execute the string [code]code[/code] as JavaScript code within the browser window. This is a call to the actual global JavaScript function [code]eval()[/code].
If [code]use_global_execution_context[/code] is [code]true[/code], 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.
Returns an interface to a JavaScript object that can be used by scripts. The [code]interface[/code] must be a valid property of the JavaScript [code]window[/code]. The callback must accept a single [Array] argument, which will contain the JavaScript [code]arguments[/code]. See [JavaScriptObject] for usage.
</description>
</method>
<methodname="pwa_needs_update"qualifiers="const">
<returntype="bool"/>
<description>
Returns [code]true[/code] if a new version of the progressive web app is waiting to be activated.
[b]Note:[/b] Only relevant when exported as a Progressive Web App.
</description>
</method>
<methodname="pwa_update">
<returntype="int"enum="Error"/>
<description>
Performs the live update of the progressive web app. Forcing the new version to be installed and the page to be reloaded.
[b]Note:[/b] Your application will be [b]reloaded in all browser tabs[/b].
[b]Note:[/b] Only relevant when exported as a Progressive Web App and [method pwa_needs_update] returns [code]true[/code].
</description>
</method>
</methods>
<signals>
<signalname="pwa_update_available">
<description>
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 [method pwa_update] to force the update to take place immediately.
