# hs.webview.usercontent

This module provides support for injecting custom JavaScript user content into your webviews and for JavaScript to post messages back to Hammerspoon.

# API Overview

Constructors - API calls which return an object, typically one that offers API methods

Methods - API calls which can only be made on an object returned by a constructor

injectScript
removeAllScripts
setCallback
userScripts

# API Documentation

# Constructors

# new


Signature	`hs.webview.usercontent.new(name) -> usercontentControllerObject`
Type	Constructor
Description	Create a new user content controller for a webview and create the message port with the specified name for JavaScript message support.
Parameters	name - the name of the message port which JavaScript in the webview can use to post messages to Hammerspoon.
Returns	the usercontentControllerObject
Notes	This object should be provided as the final argument to the `hs.webview.new` constructor in order to tie the webview to this content controller. All new windows which are created from this parent webview will also use this controller. See `hs.webview.usercontent:setCallback` for more information about the message port.
Examples	None
Source	extensions/webview/libwebview_usercontent.m line 34

# Methods

# injectScript

| | | | --------------------------------------------|-------------------------------------------------------------------------------------| | Signature | hs.webview.usercontent:injectScript(scriptTable) -> usercontentControllerObject | | Type | Method | | Description | Add a script to be injected into webviews which use this user content controller. | | Parameters |

scriptTable - a table containing the following keys which define the script and how it is to be injected: source - the javascript which is injected (required) mainFrame - a boolean value which indicates whether this script is only injected for the main webview frame (true) or for all frames within the webview (false). Defaults to true. injectionTime - a string which indicates whether the script is injected at "documentStart" or "documentEnd". Defaults to "documentStart".

| | Returns |

the usercontentControllerObject or nil if the script table was malformed in some way.

# removeAllScripts


Signature	`hs.webview.usercontent:removeAllScripts() -> usercontentControllerObject`
Type	Method
Description	Removes all user scripts currently defined for this user content controller.
Parameters	None
Returns	the usercontentControllerObject
Notes	The WKUserContentController class only allows for removing all scripts. If you need finer control, make a copy of the current scripts with `hs.webview.usercontent.userScripts()` first so you can recreate the scripts you want to keep.
Examples	None
Source	extensions/webview/libwebview_usercontent.m line 111

# setCallback


Signature	`hs.webview.usercontent:setCallback(fn) -> usercontentControllerObject`
Type	Method
Description	Set or remove the callback function to handle message posted to this user content's message port.
Parameters	fn - The function which should receive messages posted to this user content's message port. Specify an explicit nil to disable the callback. The function should take one argument which will be the message posted and any returned value will be ignored.
Returns	the usercontentControllerObject
Notes	Within your (injected or served) JavaScript, you can post messages via the message port created with the constructor like this: try { webkit.messageHandlers.name>.postMessage(message-object); } catch(err) { console.log('The controller does not exist yet'); } Where name matches the name specified in the constructor and message-object is the object to post to the function. This object can be a number, string, date, array, dictionary(table), or nil.
Examples	None
Source	extensions/webview/libwebview_usercontent.m line 133

# userScripts


Signature	`hs.webview.usercontent:userScripts() -> array`
Type	Method
Description	Get a table containing all of the currently defined injection scripts for this user content controller
Parameters	None
Returns	An array of injected user scripts. Each entry in the array will be a table containing the following keys: source - the javascript which is injected mainFrame - a boolean value which indicates whether this script is only injected for the main webview frame (true) or for all frames within the webview (false) injectionTime - a string which indicates whether the script is injected at "documentStart" or "documentEnd".
Notes	Because the WKUserContentController class only allows for removing all scripts, you can use this method to generate a list of all scripts, modify it, and then use it in a loop to reapply the scripts if you need to remove just a few scripts.
Examples	None
Source	extensions/webview/libwebview_usercontent.m line 86