<html> <head> </head> <body> <div id="div1">div1</div> <div class=".div2">aaaa</div> <div class=".div2">aaaa</div> <p>p1</p> <p>p2</p> <script> var TQObject = function(){ this.data=[]; } TQObject.prototype = {} var $=function(selecter) { this.tqOjbect = new TQObject(); if (selecter.substring(0,1) == "#") { var elem = document.getElementById(selecter.substring(1)); this.tqOjbect.data.push(elem); } else if (selecter.substring(0,1) == ".") { var elems = document.getElementsByTagName("*"); console.log(elems); var reg = new RegExp("(^|\s)" + selecter.substring(1) + "($|\s)"); console.log(reg); for (var i=0;i<elems.length;i++) { if (reg.test(elems[i].className.substring(1))) { this.tqOjbect.data.push(elems[i]); } } } else { var elems = document.getElementsByTagName(selecter); this.tqOjbect.data.push(elems); } return tqOjbect; } window.onload=function(){ var ele1 = $("#div1"); var ele2 = $(".div2"); var ele3 = $("p"); console.log(ele2); } </script> </body> </html>