Case insensitive text() comparison with DOMdocument?

How can I do a case insensitive comparison on the keyword's appearance in my content in the script below?

If I use this...

$keyword = strtolower(rseo_getKeyword($post));

$nodes = $x->query("//text()[
    contains(
    translate(.,'ABCDEFGHJIKLMNOPQRSTUVWXYZ',
                'abcdefghjiklmnopqrstuvwxyz'),
                '$keyword')

The replacement is only made on keyword matches within the content that is already lowercase. It does not appear to be doing a case insensitive lookup.

    $keyword = rseo_getKeyword($post);
    $content = $postarray['post_content']; //error: Empty string supplied in loadHTML() when I use this.
    //$content = "this is a test phrase";
    @$d = new DOMDocument();
    @$d->loadHTML($content);
    @$x = new DOMXpath($d);
    @$nodes = $x->query("//text()[contains(.,'$keyword') 
        and not(ancestor::h1) 
        and not(ancestor::h2) 
        and not(ancestor::h3) 
        and not(ancestor::h4) 
        and not(ancestor::h5) 
        and not(ancestor::h6)]");
    if ($nodes && $nodes->length) {
        $node = $n开发者_开发问答odes->item(0);
        // Split just before the keyword
        $keynode = $node->splitText(strpos($node->textContent, $keyword));
        // Split after the keyword
        $node->nextSibling->splitText(strlen($keyword));
        // Replace keyword with <b>keyword</b>
        $replacement = $d->createElement('b', $keynode->textContent);
        $keynode->parentNode->replaceChild($replacement, $keynode);
    }
    echo $d->saveHTML();die;

//text()
    [contains(translate(.,'ABCDEFGHJIKLMNOPQRSTUVWXYZ',
                        'abcdefghjiklmnopqrstuvwxyz'),                 
              '$keyword') 
    ] 

The correct expression must test if the lowercased text contains the lowercased keyword:

//text()
    [contains(translate(.,'ABCDEFGHJIKLMNOPQRSTUVWXYZ',
                          'abcdefghjiklmnopqrstuvwxyz'),                 
              translate('$keyword','ABCDEFGHJIKLMNOPQRSTUVWXYZ',
                                   'abcdefghjiklmnopqrstuvwxyz')                 
              ) 
    ] 

The text() function returns all text node children of the context node. When you call it as a parameter to translate(), the context node is a text node and so will have no text node children. Instead, use . to properly select the context node itself as you really want.

Replace your try:

contains(translate(text(), 'ABC…

with

contains(translate(., 'ABC…