jQuery traversal add() method
jQuery is a collection object. After finding the specified collection of elements through the $() method, a series of operations can be performed. After $(), it means that the collection object is already determined. What to do if you need to add a new element to this collection later? jQuery provides the add method for this, which is used to create a new jQuery object , the element is added to the set of matched elements. The argument to add() can accept almost any $(), including a jQuery selector expression, DOM element, or HTML fragment reference.
Let’s look at a simple case:
Operation: select all li elements, and then add the p element to the li collection
<ul>
<li>list item 1</li> <li>list item 3</li>
</ul>
<p>New p element</ p>
Process 1: Pass the selector
$('li').add('p')
Process 2: Pass the dom Element
$('li').add(document.getElementsByTagName('p')[0])
Another way is to dynamically create a P tag and add it to the collection , and then insert it into the specified position, but this changes the arrangement of the elements themselves
$('li').add('<p>New p element</p>'). appendTo(target location)
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title></title>
<style>
.left {
width: auto;
height: 150px;
}
.left div {
width: 150px;
height: 120px;
padding: 5px;
margin: 5px;
float: left;
background: #bbffaa;
border: 1px solid #ccc;
}
</style>
<script src="http://libs.baidu.com/jquery/1.9.1/jquery.js"></script>
</head>
<body>
<h2>add方法()</h2>
<div class="left first-div">
<div class="div">
<ul>
<li>list item 1</li>
<li>list item 2</li>
<li>list item 3</li>
</ul>
<p>新的p元素</p>
</div>
</div>
<div class="right"></div>
<br/>
<button>點擊：add傳遞元素標(biāo)簽</button>
<button>點擊：add傳遞html結(jié)構(gòu)</button>
<script type="text/javascript">
$("button:first").click(function() {
//把p元素添加到li的合集中
$('li').add('p').css('background', 'red')
})
</script>
<script type="text/javascript">
$("button:last").click(function() {
//把html結(jié)構(gòu)'<p>新的p元素</p>'
//加入到li的合集中，為了能夠在頁面上顯示
//需要再重新appendTo到指定的節(jié)點處
//值得注意：整個結(jié)構(gòu)位置都改變了
$('li').add('<p>新的p元素</p>').appendTo($('.right'))
})
</script>
</body>
</html>
