Onclick Radio button change page

<script type="text/javascript">
    function changePage(pageNum) {
        if (pageNum == 1) { var pageURL = 'page1.html'; }
        if (pageNum == 2) { var pageURL = 'page2.html'; }
        if (pageNum == 3) { var pageURL = 'page3.html'; }
        window.location.href = pageURL;
    }
</script>

<h1>Select Page:</h1>
<input type="button" onclick="changePage(1);" value="Page 1">
<input type="button" onclick="changePage(2);" value="Page 2">
<input type="button" onclick="changePage(3);" value="Page 3">