怎么获取这个答题的选项和按钮呢，想做一个自动答题的js脚本

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            <div class="center f28 text-f999">课堂问答</div>
            <div class="f22 font-w7 mb10" du-html="topic" du-scope="C53C86AB_B3B6_E1A2_0F7A_249EE0493439">这个是题目</div>
            <ul class="pl20 f18 PDFmodal-xx checkboxul" repeat-id="777EB527_09BE_EBEB_E4C6_F4C327C8966B" repeat-base-name="options"></ul>
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                <span class="PDFmodal-btn" du-click="clickbtn" du-scope="C53C86AB_B3B6_E1A2_0F7A_249EE0493439">确定</span>
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