jquery学习手记（8）遍历

层次的级别有：parent/children/sibling。

父节点

父节点遍历方法有：$.fn.parent(), $.fn.parents(), $.fn.parentsUntil(), and $.fn.closest().示例如下：

<div class="grandparent">
    <div class="parent">
        <div class="child">
            <span class="subchild"></span>
        </div>
    </div>
    <div class="surrogateParent1"></div>
    <div class="surrogateParent2"></div>
</div>

// Selecting an element's direct parent
// returns [ div.child ]
$("span.subchild").parent();
// Selecting all the parents of an element that match a given selector
// returns [ div.parent ]
$("span.subchild").parents("div.parent");
// returns [ div.child, div.parent, div.grandparent ]
$("span.subchild").parents();
// Selecting all the parents of an element up to, but *not including* the selector
// returns [ div.child, div.parent ]
$("span.subchild").parentsUntil("div.grandparent");
// Selecting the closest parent, note that only one parent will be selected
// and that the initial element itself is included in the search
// returns [ div.child ]
$("span.subchild").closest("div");
// returns [ div.child ] as the selector is also included in the search
$("div.child").closest("div");

子节点

子节点的遍历方法有：$.fn.children() and $.fn.find()。

$.fn.children()只找直接子节点，$.fn.find()迭代遍历所有的子节点。示例如下：

// Selecting an element's direct children
// returns [ div.parent, div.surrogateParent1, div.surrogateParent2 ]
$("div.grandparent").children("div");
// Finding all elements within a selection that match the selector
// returns [ div.child, div.parent, div.surrogateParent1, div.surrogateParent2 ]
$("div.grandparent").find("div"); 

兄弟节点

遍历兄弟节点的基本方法有：$.fn.prev()；$.fn.next()；$.fn.siblings()；$.fn.nextAll()；.fn.nextUntil(), $.fn.prevAll() and $.fn.prevUntil().

示例如下：

// Selecting a next sibling of the selectors
// returns [ div.surrogateParent1 ]
$("div.parent").next();
// Selecting a prev sibling of the selectors
// returns [] as No sibling exists before div.parent
$("div.parent").prev();
// Selecting all the next siblings of the selector
// returns [ div.surrogateParent1, div.surrogateParent2 ]
$("div.parent").nextAll();
// returns [ div.surrogateParent1 ]
$("div.parent").nextAll().first();
// returns [ div.surrogateParent2 ]
$("div.parent").nextAll().last();
// Selecting all the previous siblings of the selector
// returns [ div.surrogateParent1, div.parent ]
$("div.surrogateParent2").prevAll();
// returns [ div.surrogateParent1 ]
$("div.surrogateParent2").prevAll().first();
// returns [ div.parent ]
$("div.surrogateParent2").prevAll().last();

$.fn.siblings()选择所有的兄弟节点：

// Selecting an element's siblings in both directions that matches the given selector
// returns [ div.surrogateParent1, div.surrogateParent2 ]
$("div.parent").siblings();
// returns [ div.parent, div.surrogateParent2 ]
$("div.surrogateParent1").siblings();