SOURCE

$("ul li:first-child").hide();
$("#showBtn").click(function(){
    $("ul li:first-child").show();
  });
$("#showBtn").click(function(){
    $("ul li:first-child").hide(100);
  });//这是id选择器
$(".test").click(function(){
    $("p").hide();
  });//这是class选择器$("button").click(function(){
   $("button").ready(function(){
    $("a[target='_blank']").hide();
  });//这是隐藏啦target='_blank';$(document).ready(function(){

 
 $(document).ready(function(){
  $("tr:even").css("background-color","pink");
  $("tr:odd").css("background-color","White");
});
 $("button2").ready(function(){
    $("#div1").fadeIn().fadeTo("slow",0.4);
    $("#div2").fadeIn("slow").fadeTo("slow",0.15);
    $("#div3").fadeIn(3000).fadeTo("slow",0.7);
  });
$("button2").click(function(){
    $("#div1").fadeOut();
    $("#div2").fadeOut("slow");
    $("#div3").fadeOut(8000);
  });
$(document).ready(function()
  {
  $("button").click(function(){
    $("#p1").css("color","pink")
      .slideUp(2000)
      .slideDown(2000);
  });
});

<h1>Heading</h1>
<ul>
  <li>A1</li>
  <li>A2</li>
</ul>
<ul>
  <li>B1</li>
  <li>B2</li>
</ul>
<button id="showBtn">显示</button>
<button id="hideBtn">隐藏</button>
<p><a href="http://www.liaoxuefeng.com/wiki/001434446689867b27157e896e74d51a89c25cc8b43bdb3000/00143449922400335c44d4b8c904ff29a78fd4334347131000/">HTML 教程</a></p>
<p><a href="http://www.liaoxuefeng.com/wiki/001434446689867b27157e896e74d51a89c25cc8b43bdb3000/00143449922400335c44d4b8c904ff29a78fd4334347131000/">CSS 教程</a></p>
<button class="test">点我啊</button>
<hr/>
<p><a href="http://www.runoob.com/html/" target="_blank">HTML 教程</a></p>
<p><a href="http://www.runoob.com/css/">CSS 教程</a></p>
<button >点我</button>
<hr/>
<h1 >我的宿舍，我的，我的！</h1>

<table border="2"; width="650px";hight="250px">
<tr>
  <th>宿舍名</th>
  <th>编号</th>
</tr>
<tr>
<td>2317</td>
<td>001</td>
</tr>
<tr>
<td>2318</td>
<td>002</td>
</tr>
<tr>
<td>2319</td>
<td>003</td>
</tr>
<tr>
<td>2320</td>
<td>004</td>
</tr>

</table><hr/>
<button 2>点击淡入 div 元素。</button 2>
<br><br>
<div id="div1" style="width:80px;height:80px;display:none;background-color:red;"></div><br>
<div id="div2" style="width:80px;height:80px;displa y:none;background-color:green;"></div><br>
<div id="div3" style="width:80px;height:80px;display:none;background-color:blue;"></div><hr/>
<p id="p1">菜鸟教程!!</p>
<button >点我</button>

p{color:red;}
h1,th,td{text-align:center;}