input输入内容回车生成标签代码

<style>
#tag a{margin-right:10px;color:blue;border:dotted 1px blue;cursor:pointer}</style>
<span id="tag"></span><input type="text" onkeydown="addTag(event,this)" />
<script type="text/javascript">
    function addTag(e, o) {
        if (e.keyCode == 13 && o.value != '') {
            var a = document.createElement('a');
            a.innerHTML = o.value + ' x';
            a.onclick = function () { this.onclick = null; document.getElementById('tag').removeChild(this); };
            document.getElementById('tag').appendChild(a);
            o.value = '';
            return false;
        }
    }
</script>