一个简单的jQuery问题，click后没有反应？？怎么办

<div  id="q">
<p  id="a">
<span>1</span> <span>2</span> <span>3</span> <span>4</span>
<span>5</span> <span>6</span> <span>7</span> <span>8</span>
<span>9</span> <span>10</span> <span>11</span> span>12</span>
<span>13</span> <span>14</span> <span>15</span> <span>16</span> <span>17</span> <span>18</span> <span>19</span> <span>20</span> <span>21</span>
</p>
<p  id="b">显示</p>
</div>
<style>
    #q{
        border:1px red solid;
        width:300px;
        }
    #a{
        column-count:3;
        column-width:80px;
        column-gap:10px;
        width:300px;
        height:100px;//！！！！！！
        overflow:hidden;//!！！！！！
        line-height:30px;
        border:0px red solid;
        margin:0px;
        }
    span:not(#b){
        border:1px red solid;    
        margin:10px 10px;    
        }    
    #b{
            column-span:all;
            margin:10px 50px;
            border:1px black solid;
            text-align:center;        
            }
    </style>

下面是jQuery部分：

$("#b").click(function(){
        $("#a").height()==100?$("#a").removeAttr("height"):$("#a").height(100);
        })

希望多次点击“显示”，内容不断切换显示和隐藏(部分隐藏)状态，
现在问题是当点击"显示"，没有反应？？求大神给招
下面是截图：