<script type="text/javascript">

//另一个

    function get_previousSibling(z){

        var a=z.previousSibling;

        while(a.nodeType!=1){

            a=a.previousSibling;

        }

        return=a;

    }

    var a=document.getElementsByName('li')[a.length-1];

    document.write(a.nodeName+"="+a.innerHTML);

    var b=a.previousSibling;

    document.write(b.nodeName+'='+b.innerHTML)

</script>