Document the wikipage.content hook

There is some text in the mw.hook documentation section, but that's
really intended to document mw.hook.

Change-Id: I2afb74a1124123220b26b50b3df64dd7bae80208

diff --git a/resources/mediawiki.page/mediawiki.page.startup.js b/resources/mediawiki.page/mediawiki.page.startup.js
index 3846681..e354106 100644 (file)
--- a/resources/mediawiki.page/mediawiki.page.startup.js
+++ b/resources/mediawiki.page/mediawiki.page.startup.js
@@ -17,9 +17,20 @@
                mw.util.init();
 
                /**
+                * Fired when wiki content is being added to the DOM
+                *
+                * It is encouraged to fire it before the main DOM is changed (when $content
+                * is still detatched).  However, this order is not defined either way, so you
+                * should only rely on $content itself.
+                *
+                * This includes the ready event on a page load (including post-edit loads)
+                * and when content has been previewed with LivePreview.
+                *
                 * @event wikipage_content
                 * @member mw.hook
-                * @param {jQuery} $content
+                * @param {jQuery} $content The most appropriate element containing the content,
+                *   such as #mw-content-text (regular content root) or #wikiPreview (live preview
+                *   root)
                 */
                mw.hook( 'wikipage.content' ).fire( $( '#mw-content-text' ) );
        } );