Core: Remove ancestor visibility requirement from `:focusable` selector

* Check computed visibility in addition to :visible
* Add tests for nested visibility override

Fixes #14596
Closes gh-1583

tests/unit/core/core.html

@@ -80,6 +80,11 @@
	<div id="visibilityHiddenAncestor" style="visibility: hidden;">
		<input id="visibilityHiddenAncestor-input">
		<span tabindex="1" id="visibilityHiddenAncestor-span">.</span>

		<span id="nestedVisibilityOverrideAncestor" style="visibility: visible">
			<input id="nestedVisibilityOverrideAncestor-input">
			<span tabindex="1" id="nestedVisibilityOverrideAncestor-span">.</span>
		</span>
	</div>

	<span tabindex="1" id="displayNone-span" style="display: none;">.</span>

tests/unit/core/selector.js

@@ -125,14 +125,17 @@ test( "focusable - disabled elements", function() {
} );

test( "focusable - hidden styles", function() {
	expect( 8 );
	expect( 10 );

	isNotFocusable( "#displayNoneAncestor-input", "input, display: none parent" );
	isNotFocusable( "#displayNoneAncestor-span", "span with tabindex, display: none parent" );

	isNotFocusable( "#visibilityHiddenAncestor-input", "input, visibility: hidden parent" );
	isNotFocusable( "#visibilityHiddenAncestor-span", "span with tabindex, visibility: hidden parent" );

	isFocusable( "#nestedVisibilityOverrideAncestor-input", "input, visibility: visible parent but visibility: hidden grandparent" );
	isFocusable( "#nestedVisibilityOverrideAncestor-span", "span with tabindex, visibility: visible parent but visibility: hidden grandparent " );

	isNotFocusable( "#displayNone-input", "input, display: none" );
	isNotFocusable( "#visibilityHidden-input", "input, visibility: hidden" );

@@ -210,14 +213,17 @@ test( "tabbable - disabled elements", function() {
} );

test( "tabbable - hidden styles", function() {
	expect( 8 );
	expect( 10 );

	isNotTabbable( "#displayNoneAncestor-input", "input, display: none parent" );
	isNotTabbable( "#displayNoneAncestor-span", "span with tabindex, display: none parent" );

	isNotTabbable( "#visibilityHiddenAncestor-input", "input, visibility: hidden parent" );
	isNotTabbable( "#visibilityHiddenAncestor-span", "span with tabindex, visibility: hidden parent" );

	isTabbable( "#nestedVisibilityOverrideAncestor-input", "input, visibility: visible parent but visibility: hidden grandparent" );
	isTabbable( "#nestedVisibilityOverrideAncestor-span", "span with tabindex, visibility: visible parent but visibility: hidden grandparent " );

	isNotTabbable( "#displayNone-input", "input, display: none" );
	isNotTabbable( "#visibilityHidden-input", "input, visibility: hidden" );

ui/focusable.js

@@ -34,26 +34,17 @@ $.ui.focusable = function( element, hasTabindex ) {
		if ( !element.href || !mapName || map.nodeName.toLowerCase() !== "map" ) {
			return false;
		}
		img = $( "img[usemap='#" + mapName + "']" )[ 0 ];
		return !!img && visible( img );
		img = $( "img[usemap='#" + mapName + "']" );
		return img.length > 0 && img.is( ":visible" );
	}
	return ( /^(input|select|textarea|button|object)$/.test( nodeName ) ?
		!element.disabled :
		"a" === nodeName ?
			element.href || hasTabindex :
			hasTabindex ) &&

		// The element and all of its ancestors must be visible
		visible( element );
		$( element ).is( ":visible" ) && $( element ).css( "visibility" ) === "visible";
};

function visible( element ) {
	return $.expr.filters.visible( element ) &&
		!$( element ).parents().addBack().filter( function() {
			return $.css( this, "visibility" ) === "hidden";
		} ).length;
}

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