怎么改成 最多选两项 这样的结果是三个同时都可选
<form>
<label for="joging">慢跑</label>
<input type="checkbox" name="interest" id="joging" />
<br />
<label for="hiking">登山</label>
<input type="checkbox" name="interest" id="hiking" />
<br />
<label for="basket">篮球</label>
<input type="checkbox" name="interest" id="basket"/>
<br />
<label for="email">输入你的邮箱地址</label>
<input type="email" id="email" placeholder="Enter email">
</form>