<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
<div id="d1">
我是div1
</div>
<div class="d2">
<p>哈哈</p>
</div>
<button type="button" id="b1">我是button1</button>
</body>
<script type="text/javascript" src="../images/jquery-3.4.1.min.js"></script>
<script type="text/javascript">
document.getElementById("b1").onclick = function(){
/* 获取jQuery对象的对应属性 */
/*有时jQuery对象名也没有$ */
var $d1 = $("#d1");
var shuxing = $("#d1").attr("id");
alert(shuxing);
alert($d1 instanceof jQuery);
var dom1 = $d1.get(0);
alert(dom1 instanceof jQuery);
/* DOM对象转为jQuery对象 */
var d3 = $(dom1);
alert(d3 instanceof jQuery);
}
</script>
</html>