<!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>