XPath选择父母兄弟的后代

Question

This html is within my page:

<tr>
    <td class="padded2" bgcolor="#103A74"><font color="White">Refine by Vehicle Types</font></td>
    </tr><tr>
        <td class="padded2" bgcolor="White"><div>
            <table border="0">
                <tr>
                    <td class="padded2"><font color="#103A74"><ul><li><a class="padded2"> Cars</a></li><li><a class="padded2">Marine Engines</a></li><li><a class="padded2">Trucks</a></li></ul></font></td>
                </tr>
            </table>
        </div></td>
</tr>

I'm wanting to scrape "Cars" and "Trucks" based on the fact that they are after "Refine by Vehicle Type". I've tried many diferent ways and this is as close as I can get, but returns NULL.

$Nodes = $xPath->query("//tr/td/font[text()[contains(., 'Refine by Vehicle Type')]]/following-sibling::tr/td/div/table/tr/td/font/ul/li/a")->item(0)->nodeValue;

What am I missing?

Answer 1

Your error is in this:

...font[...]/following-sibling::tr/...

It is easy to see that in the provided XML fragment, the <font> element has no sibling elements.

Here is one correct XPath expression:

  tr[td[contains(., 'Refine by Vehicle Types')]]
      /following-sibling::tr
        /td/div/table
                 /tr/td/font
                         /ul/li/a

When evaluated against the following XML document (your provided fragment wrapped by a <table>):

<table>
    <tr>
        <td class="padded2" bgcolor="#103A74">
            <font color="White">Refine by Vehicle Types</font>
        </td>
    </tr>
    <tr>
        <td class="padded2" bgcolor="White">
            <div>
                <table border="0">
                    <tr>
                        <td class="padded2">
                            <font color="#103A74">
                                <ul>
                                    <li>
                                        <a class="padded2"> Cars</a>
                                    </li>
                                    <li>
                                        <a class="padded2">Marine Engines</a>
                                    </li>
                                    <li>
                                        <a class="padded2">Trucks</a>
                                    </li>
                                </ul>
                            </font>
                        </td>
                    </tr>
                </table>
            </div>
        </td>
    </tr>
</table>

the following elements are selected:

<a class="padded2"> Cars</a>
<a class="padded2">Marine Engines</a>
<a class="padded2">Trucks</a>

XSLT - based verification:

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>

 <xsl:template match="/*">
  <xsl:copy-of select=
  "tr[td[contains(., 'Refine by Vehicle Types')]]
      /following-sibling::tr
        /td/div/table
                 /tr/td/font
                         /ul/li/a
  "/>
 </xsl:template>
</xsl:stylesheet>

when this transformation is applied on the XML document above, the selected elements are output:

<a class="padded2"> Cars</a>
<a class="padded2">Marine Engines</a>
<a class="padded2">Trucks</a>

I would recommend using an XPath Visualizer to get quickly up with writing correct and elegant XPath expressions.