<div class="h5-header">
<header class="m-header" style="display:block">
<a class="icon logo"></a>
<a href="#" class="title">标题</a>
<a href="javascript:void(0);" οnclick="change()" class="icon search"></a>
<a class="icon nologin"></a>
<a class="icon nav"></a>
</header>

<header class="x-search-panel" style="display:none">
<div class="x-search">
    <div class="searchbox">
        <form action="javascript:void(0);">
            <input type="search" value="">
        </form>
        <a href="javascript:void(0);" οnclick="change()" class="cancle">取消</a>
    </div>
</div>
<div class="toast">
</div>
</header>
</div>
<div style="height:199px;background-color:#eee;">占位</div>

<script type="text/javascript">
    var header = document.getElementsByClassName("m-header")[0];
    var search = document.getElementsByClassName('x-search-panel')[0];

    function change() {
        if (search.style.display == 'none') {
            header.style.display = 'none';
            search.style.display = 'block';
        } else {
            header.style.display = 'none';
        }
    }
</script>