全选中选择器 (“*”)
all selector
示例
找到document中的每个元素（包括head、body，等等）。注意，如果你的浏览器具有一个扩展/附加项，启用了向DOM插入一个<script>或者<link>元素，这个元素也会被点数进去。
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>all demo</title>
<style>
h3 {
margin: 0;
}
div, span, p {
width: 80px;
height: 40px;
float: left;
padding: 10px;
margin: 10px;
background-color: #EEEEEE;
}
</style>
<script src="https://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
<div>DIV</div>
<span>SPAN</span>
<p>P <button>Button</button></p>
<script>
var elementCount = $( "*" ).css( "border", "3px solid red" ).length;
$( "body" ).prepend( "<h3>" + elementCount + " elements found</h3>" );
</script>
</body>
</html>
演示结果
找到document.body内部的所有元素，从而一些元素，比如说head、script等等被排除在外。
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>all demo</title>
<style>
h3 {
margin: 0;
}
div, span, p {
width: 80px;
height: 40px;
float: left;
padding: 10px;
margin: 10px;
background-color: #EEEEEE;
}
#test {
width: auto;
height: auto;
background-color: transparent;
}
</style>
<script src="https://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
<div id="test">
<div>DIV</div>
<span>SPAN</span>
<p>P <button>Button</button></p>
</div>
<script>
var elementCount = $( "#test" ).find( "*" ).css( "border", "3px solid red" ).length;
$( "body" ).prepend( "<h3>" + elementCount + " elements found</h3>" );
</script>
</body>
</html>
演示结果