通过简单圆顶解析的查找方法，葡萄html元素的主要规则是什么

Question

我正在使用simple_html_dome，我想抓住经验，教育和头衔。

根据我的代码，我收到（在find()上调用成员函数null）错误消息，但标题显示错误是（$notrmjobs = $item->find('div[class=norm-jobs-wrapper]',0);）。

通过find方法捕获HTML标记的核心规则是什么？

<div class="boxed">
    <div class="row">
        <div class="col-md-12">
            <div class="norm-jobs-wrapper" onclick="DivOpen('id=734675&fcatId=1&ln=1');">
                <div class="row">

                    <div class="col-sm-3 col-sm-push-3">
                        <!--<div class="row">
                                <div class="col-sm-12">
                                    <div class="comp_logo"><img src="images/38951.jpg" alt=""></div>
                                </div>
                            </div>-->


                    </div>
                    <div class="col-sm-9 col-sm-pull-9">
                        <div class="row">
                            <div class="col-sm-12">
                                <div class="comp-name-text">GBA Techno Pvt. Ltd.</div>
                            </div>
                            <div class="col-sm-12">
                                <div class="job-title-text">
                                    <a onclick="clickJObTitle()" target="_blank" href="jobdetails.asp?id=734675&fcatId=1&ln=1">
                                        Sr. Executive, Accounts
                                    </a>
                                </div>
                            </div>


                            <div class="col-sm-12">
                                <div class="edu-text">
                                    <div class="row">
                                        <div class="col-sm-2">
                                            <div class="edu-text-s">
                                                Education:
                                            </div>
                                        </div>
                                        <div class="col-sm-10">
                                            <div class="edu-text-d">
                                                Masters/ MBA in Accounts or Finance from any reputed university

                                            </div>
                                        </div>
                                    </div>
                                </div>
                            </div>


                        </div>
                    </div>
                    <div class="col-sm-12">
                        <div class="row">
                            <div class="col-sm-9">
                                <div class="exp-text">
                                    <div class="row">
                                        <div class="col-sm-2">
                                            <div class="exp-text-s">Experience:</div>
                                        </div>
                                        <div class="col-sm-10">
                                            <div class="exp-text-d">
                                                At least 3 year(s)
                                            </div>
                                        </div>
                                    </div>
                                </div>
                            </div>
                            <div class="col-sm-3">
                                <div class="dead-text">
                                    <div class="dead-text-s">Deadline:&nbsp;</div>
                                    <div class="dead-text-d">
                                        <strong>Dec 13, </strong>2017
                                    </div>
                                </div>
                            </div>
                        </div>
                    </div>

                </div>
            </div>
        </div>
        <?php 
    include 'simple_html_dom.php';

    $html = file_get_html('http://jobs.bdjobs.com/jobsearch.asp?fcatId=1&icatId=');
    $boxed =   $html->find('div[class=boxed]',0);
    $raw = $boxed->find('div[class=row]');
    foreach($raw as $key => $loop){
        $item = $loop->find('div[class=col-md-12]',0);
        $notrmjobs = $item->find('div[class=norm-jobs-wrapper]',0);
        $raw = $notrmjobs->find('div[class=row]',0);
        $sdivice = $raw->find('div[class=col-sm-9 col-sm-pull-9]',0);
        $sraw = $sdivice->find('div[class=row]',0);
        $asraw = $sraw->find('div[class=col-sm-12]',0);
        $title = $asraw->find('div[class=comp-name-text]',0)->plaintext;
        echo $title;
    }
?>