[addFirstLastClasses] Common behaviour for determining the first/last…

… visible item

js/index.php

@@ -34,6 +34,7 @@
 	'widgets/dialog.js',
 	'widgets/page.sections.js',
 	'widgets/collapsible.js',
+	'widgets/addFirstLastClasses.js',
 	'widgets/collapsibleSet.js',
 	'jquery.mobile.fieldContain.js',
 	'jquery.mobile.grid.js',

js/widgets/addFirstLastClasses.js

@@ -0,0 +1,38 @@
+//>>excludeStart("jqmBuildExclude", pragmas.jqmBuildExclude);
+//>>description: Mark first and last visible item with classes ui-first-child resp. ui-last-child.
+//>>label: addFirstLastClasses
+//>>group: Widgets
+
+define( [ "jquery", "../../jquery.mobile.core" ], function( $ ) {
+//>>excludeEnd("jqmBuildExclude");
+(function( $, undefined ) {
+
+$.mobile.behaviors.addFirstLastClasses = {
+	_getVisibles: function( $els, create ) {
+		var visibles;
+
+		if ( create ) {
+			visibles = $els.not( ".ui-screen-hidden" );
+		} else {
+			visibles = $els.filter( ":visible" );
+			if ( visibles.length === 0 ) {
+				visibles = $els.not( ".ui-screen-hidden" );
+			}
+		}
+
+		return visibles;
+	},
+
+	_addFirstLastClasses: function( $els, $visibles, create ) {
+		$els.removeClass( "ui-first-child ui-last-child" );
+		$visibles.eq( 0 ).addClass( "ui-first-child" ).end().last().addClass( "ui-last-child" );
+		if ( !create ) {
+			this.element.trigger( "updatelayout" );
+		}
+	}
+};
+
+})( jQuery );
+//>>excludeStart("jqmBuildExclude", pragmas.jqmBuildExclude);
+});
+//>>excludeEnd("jqmBuildExclude");