tutorials/platform/web/javascript_bridge

[giscus[bot]]

tutorials/platform/web/javascript_bridge

In web builds, the JavaScriptBridge singleton allows interaction with JavaScript and web browsers, and can be used to implement some functionalities unique to the web platform. Interacting with Jav...

https://docs.godotengine.org/en/4.3/tutorials/platform/web/javascript_bridge.html

[codeJester27]

REALLY important thing that does not seem to be mentioned, if you do not include an argument in your callback's function, it will not be called by Javascript.

Bad:

extends Node

var _callback_ref = JavaScriptBridge.create_callback(_my_callback)

# Try to call the callback function every time the user clicks the window
func _ready():
	var window = JavaScriptBridge.get_interface("window")
	window.onclick = _callback_ref

# This won't ever run because it has no argument!!!
func _my_callback():
	JavaScriptBridge.eval("console.log(\"hello!\")")

Good:

extends Node

var _callback_ref = JavaScriptBridge.create_callback(_my_callback)

# Try to call the callback function every time the user clicks the window
func _ready():
	var window = JavaScriptBridge.get_interface("window")
	window.onclick = _callback_ref

# This will run because it has an argument
func _my_callback(args):
	JavaScriptBridge.eval("console.log(\"hello!\")")

[Calinou]

Pull request opened:

• Mention callback argument count in The JavaScript bridge singleton godot-docs#10162

[Faless]

Note that the updated documentation is inaccurate, and the callback should take exactly one array argument (the argument object converted to an Array).

I've opened godotengine/godot-docs#10450 to clarify that, and godotengine/godot#100939 to also explain it in the in-editor docs for the create_callback function.