jquery-ui/ui/focusable.js

/*!
 * jQuery UI Focusable @VERSION
 * http://jqueryui.com
 *
 * Copyright OpenJS Foundation and other contributors
 * Released under the MIT license.
 * http://jquery.org/license
 */

//>>label: :focusable Selector
//>>group: Core
//>>description: Selects elements which can be focused.
//>>docs: http://api.jqueryui.com/focusable-selector/

( function( factory ) {
	"use strict";

	if ( typeof define === "function" && define.amd ) {

		// AMD. Register as an anonymous module.
		define( [ "jquery", "./version" ], factory );
	} else {

		// Browser globals
		factory( jQuery );
	}
} )( function( $ ) {
"use strict";

// Selectors
$.ui.focusable = function( element, hasTabindex ) {
	var map, mapName, img, focusableIfVisible, fieldset,
		nodeName = element.nodeName.toLowerCase();

	if ( "area" === nodeName ) {
		map = element.parentNode;
		mapName = map.name;
		if ( !element.href || !mapName || map.nodeName.toLowerCase() !== "map" ) {
			return false;
		}
		img = $( "img[usemap='#" + mapName + "']" );
		return img.length > 0 && img.is( ":visible" );
	}

	if ( /^(input|select|textarea|button|object)$/.test( nodeName ) ) {
		focusableIfVisible = !element.disabled;

		if ( focusableIfVisible ) {

			// Form controls within a disabled fieldset are disabled.
			// However, controls within the fieldset's legend do not get disabled.
			// Since controls generally aren't placed inside legends, we skip
			// this portion of the check.
			fieldset = $( element ).closest( "fieldset" )[ 0 ];
			if ( fieldset ) {
				focusableIfVisible = !fieldset.disabled;
			}
		}
	} else if ( "a" === nodeName ) {
		focusableIfVisible = element.href || hasTabindex;
	} else {
		focusableIfVisible = hasTabindex;
	}

	return focusableIfVisible && $( element ).is( ":visible" ) && visible( $( element ) );
};

// Support: IE 8 only
// IE 8 doesn't resolve inherit to visible/hidden for computed values
function visible( element ) {
	var visibility = element.css( "visibility" );
	while ( visibility === "inherit" ) {
		element = element.parent();
		visibility = element.css( "visibility" );
	}
	return visibility === "visible";
}

$.extend( $.expr.pseudos, {
	focusable: function( element ) {
		return $.ui.focusable( element, $.attr( element, "tabindex" ) != null );
	}
} );

return $.ui.focusable;

} );