Create displaymessage.js

We call this code, so we should have a local copy of it in the repo to be able to change and fix things.

src/User-Timotheus-Canens/displaymessage.js

@@ -0,0 +1,42 @@
+/**
+ * The old mw.util.jsMessage function before https://gerrit.wikimedia.org/r/#/c/17605/, which
+ * introduced the silly auto-hide function. Also with the original styles.
+ * Add a little box at the top of the screen to inform the user of
+ * something, replacing any previous message.
+ * Calling with no arguments, with an empty string or null will hide the message
+ *
+ * @param message {mixed} The DOM-element, jQuery object or HTML-string to be put inside the message box.
+ * @param className {String} Used in adding a class; should be different for each call
+ * to allow CSS/JS to hide different boxes. null = no class used.
+ * @return {Boolean} True on success, false on failure.
+ */
+function displayMessage( message, className ){
+	if ( !arguments.length || message === '' || message === null ) {
+		$( '#display-message' ).empty().hide();
+		return true; // Emptying and hiding message is intended behaviour, return true
+	} else {
+		// We special-case skin structures provided by the software. Skins that
+		// choose to abandon or significantly modify our formatting can just define
+		// an mw-js-message div to start with.
+		var $messageDiv = $( '#display-message' );
+		if ( !$messageDiv.length ) {
+			$messageDiv = $( '<div id="display-message" style="margin:1em;padding:0.5em 2.5%;border:solid 1px #ddd;background-color:#fcfcfc;font-size: 0.8em"></div>' );
+			if ( mw.util.$content.length ) {
+				mw.util.$content.prepend( $messageDiv );
+			} else {
+				return false;
+			}
+		}
+		if ( className ) {
+			$messageDiv.prop( 'class', 'display-message-' + className );
+		}
+		if ( typeof message === 'object' ) {
+			$messageDiv.empty();
+			$messageDiv.append( message );
+		} else {
+			$messageDiv.html( message );
+		}
+		$messageDiv.slideDown();
+		return true;
+	}
+}