怎样设置点击<a>标签,然后修改表单样式？

<a id="replyA" href="#" onclick="changeForm();">回复</a> <form id="replyForm" action="" method="post" style="display: none"> <input type="text" style="width:600px;height: 50px;"/><br/> <input type="submit" value="提交回复"/> </form> 比如，点击回复然后修改replyForm的样式display为block