判断节点包含

• 元素包含

contains基本兼容
用法node.contains( otherNode )
compareDocumentPosition感觉比较奇怪,据说是这样

The Node.compareDocumentPosition() method compares the position of the
current node against another node in any other document.
返回值分为6个数字
jquery的selector-native有个原生方法contains这样写的

contains: function( a, b ) {var adown &＃61; a.nodeType &＃61;&＃61;&＃61; 9 ? a.documentElement : a, bup &＃61; b && b.parentNode;return a &＃61;&＃61;&＃61; bup || !!( bup && bup.nodeType &＃61;&＃61;&＃61; 1 && adown.contains(bup) );}

比较容易理解

update 2015-01-27

开发凤凰焦点项目的时候&＃xff0c;有用到判断元素包含关系的contains,当时第一反应是想到jquery取子元素的方式.&＃xff08;之前看过实现方式的,忘了2333...&＃xff09;当然不是用的contains&＃xff0c;因为相比取子元素更适合关系判断.那么jq是怎么取的呢&＃xff1f;

• node.nextSibling
• node.previousSibling
  没错&＃xff0c;就是这俩属性,traversing.js脚本可见

jQuery.extend({//directiondir: function( elem, dir, until ) {var matched &＃61; [],truncate &＃61; until !&＃61;&＃61; undefined;while ( (elem &＃61; elem[ dir ]) && elem.nodeType !&＃61;&＃61; 9 ) {if ( elem.nodeType &＃61;&＃61;&＃61; 1 ) { //nodeType:1 --> elementif ( truncate && jQuery( elem ).is( until ) ) {break;}matched.push( elem );}}return matched;},sibling: function( n, elem ) {var matched &＃61; [];for ( ; n; n &＃61; n.nextSibling ) {if ( n.nodeType &＃61;&＃61;&＃61; 1 && n !&＃61;&＃61; elem ) {matched.push( n );}}return matched;}
});

siblings: function( elem ) {return jQuery.sibling( ( elem.parentNode || {} ).firstChild, elem );
},
children: function( elem ) {return jQuery.sibling( elem.firstChild );
}