Untitled

<div id="main">

    <div id="div1">Keep this div</div>

    <div>1</div>

    <div>2</div>

    <div>3</div>

    <p>4</p>  

    <a href="">Keep this hyperlink</a>

</div>

<button id="button">Clear</button>

<script class="cssdeck" src="//cdnjs.cloudflare.com/ajax/libs/jquery/1.8.0/jquery.min.js"></script>

$('#button').on('click', function () {

  $('#div1').nextAll(':not(a)').remove();

});