正则匹配求助

Question

    <div class="aaa">
        <div data-id='123' class="bbb">
            234567
            <div>
                123456789
            </div>
        </div>
    </div>
怎么用正则匹配获得class="aaa"内的所有内容呢

Answer 1

估计很困难,class="aaa"标签名随机的,而且有可能 class="aaa"还嵌套的有n个 
<div class="aaa">
        <div data-id='123' class="aaa">
            234567
            <div class="aaa">
                123456789
            </div>
        </div>
    </div>呢?