Im trying to get a drop down box to duplicate when a user presses a button but it just refreshes the page on click

HTML Code:
    <form id="form">
		<select id="time2" name="time2">

		  <option value="N/A">N/A</option>
		  <option value="Archery range">Archery Range</option>
  		  <option value="Rifle range">Rifle Range</option>
  		  <option value="Climbing wall">Climbing Wall</option>
  		  <option value="Grass sledges">Glass Sledges</option>
  		  <option value="Go karts">Go Karts</option>
		  <option value="Camp fire circle">Camp Fire Circle</option>

        <button id="add">Add</button>


 document.getElementById( 'add' ).addEventListener( 'click', function ( event ) {
        var select = document.getElementById( 'select' ).cloneNode( true );
        document.getElementById( 'form' ).appendChild( select );
    }, false );​