html部分：

<div id="box">

    <div id="box_title">标题</div>

    <div id="box_content">11111111<br/>2222222<br/>333333</div>

</div>

css部分：

<style>

    #box {position:fixed;bottom:;z-index:;width:100%;}

    #box_title {background: #ff2a2a;}

    #box_content {display: none;}

</style>

js部分：

<script>

    window.onload = function(){

        document.querySelector("#box_title").addEventListener("click",function(){

            var o = document.querySelector("#box_content")

            if(o.className == '') {

                o.style.display = 'block';

                o.className = 'active';

            }else{

                o.style.display = 'none';

                o.className = '';

            }

        },false);

    }

</script>