代码示例：
<!DOCTYPE html> <html> <head> <title>selectorDemo2.html</title> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="this is my page"> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <script type="text/javascript" src="../js/jquery-3.3.1.js"></script> <style type="text/css"> .abc{ background:red; } </style> <script type="text/javascript"> $(function(){ //:first //$("li:first").addClass("abc"); //:last //$("li:last").addClass("abc"); //:not(selector) //$("li:not('#l3')").addClass("abc"); //:even //$("li:even").addClass("abc"); //:odd //$("li:odd").addClass("abc"); //:eq //$("li:eq(0)").addClass("abc"); //:gt //$("li:gt(2)").addClass("abc"); //:lt //$("li:lt(2)").addClass("abc"); //:header //$(":header").addClass("abc"); //animate $(".div1").animate({300},"slow").css("background-color","blue"); }); </script> </head> <body> <ul> <li>list1</li> <li>list2</li> <li id="l3">list3</li> <li>list4</li> <li>list5</li> </ul> <h1>h111111</h1> <h2>h22222</h2> <div class="div1">div11111111</div> </body> </html>