有大神用过PHP Simple HTML DOM Parser这个吗 求指教

<code><table width="100%" border="0" cellpadding="0" cellspacing="0" class="titleTop2">
    <tr>
        <td class="pageAlign">
            <table cellpadding="0" width="100%" class="displayTag" cellspacing="1" border="0" id="user">
                <thead>
                    <tr>
                        <th align="center" width="10%" class="sortable">课程号</th>


<p>获取到  课程号   这三个字</p>

                            
                        


                                                                                                                        
                     <h2>回复内容：</h2>
                      
                                                            
<p>如何用这个获取</p>

<pre class="brush:php;toolbar:false"><code><table width="100%" border="0" cellpadding="0" cellspacing="0" class="titleTop2">
    <tr>
        <td class="pageAlign">
            <table cellpadding="0" width="100%" class="displayTag" cellspacing="1" border="0" id="user">
                <thead>
                    <tr>
                        <th align="center" width="10%" class="sortable">课程号</th>


<p>获取到  课程号   这三个字</p>

                            
                        
            <p class="answer fmt" data-id="1020000002529999">
                                    
</p>
<pre class="brush:php;toolbar:false"><code>php</code><code><br>$html = >>>XML


<table>
<th align="center" width="10%" class="sortable">
                课程号
                </th>
</table>


XML

$xml = simplexml_load_string($html)

$ths = $xml->xpath("/table/th/[@category='sortable']")

print_r($ths[0])

// 课程号
</code>

<code>$html = "<table>...</table>";
$htmlObject = str_get_html($html);
$th = $htmlObject->find('th', 0);
$text = $th->plaintext;
</code>