JS使用for.in方法的books数组输出

题主要的代码如下

<script>
    var books = ['《JavaScript前段开发案列教程》', "《Node.js核心基础教程》", "《HTML5移动Web开发", "《高级办公软件应用》"];
    for (var i in books) document.write(books[i] + '<br>');

    document.write('<hr>')
    function extend(books1, books2) {
        for (var i in books2) books1.push(books2[i]);
    }
    var books1 = [];
    extend(books1, books);
    for (var i in books) document.write(books[i] + '<br>');
</script>
<table border="0" cellpadding="10" cellspacing="0" style="border:solid 1px #2487c9;">
    <tr><td colspan="2" style="background:#2487c9;color:#fff">个人信息</td></tr>
    <tr><td width="80">姓　　名：</td><td><input type="text" /></td></tr>
    <tr><td>性　　别：</td><td><input type="radio" name="sex" />男　<input type="radio" name="sex" />女</td></tr>
    <tr><td>爱　　好：</td><td><input type="checkbox" />游泳　<input type="checkbox" />读书　<input type="checkbox" />跑步</td></tr>
    <tr><td>住址：</td><td><select><option>--请选择--</option><option>北京</option><option>上海</option><option>深圳</option></select></td></tr>
    <tr><td>自我介绍：</td><td><textarea cols="80" rows="8"></textarea></td></tr>
    <tr><td></td><td><input type="submit" value="提交" /></td></tr>
</table>

有帮助麻烦点下【采纳该答案】，谢谢~~

for(var i in list)
console.log(list[i]);