11.8.1. Problem

11.8.2. Solution

$patterns = array('\bdog\b/', '\bcat\b');
$replacements = array('<b style="color:black;background-color=#FFFF00">dog</b>',
                      '<b style='color:black;background-color=#FF9900">cat</b>');
while ($page) {
    if (preg_match('{^([^<]*)?(</?[^>]+?>)?(.*)$}',$page,$matches)) {
        print preg_replace($patterns,$replacements,$matches[1]);
        print $matches[2];
        $page = $matches[3];
    }
}

11.8.3. Discussion

$colors = array('FFFF00','FF9900','FF0000','FF00FF',
                '99FF33','33FFCC','FF99FF','00CC33'); 

// build search and replace patterns for regex 
$patterns = array();
$replacements = array();
for ($i = 0, $j = count($words); $i < $j; $i++) {
    $patterns[$i] = '/\b'.preg_quote($words[$i], '/').'\b/';
    $replacements[$i] = '<b style="color:black;background-color:#' .
                         $colors[$i % 8] .'">' . $words[$i] . '</b>';
}

// retrieve page 
$fh = fopen($url,'r') or die($php_errormsg);
while (! feof($fh)) {
    $s .= fread($fh,4096);
}
fclose($fh);

if ($j) {
    while ($s) {
        if (preg_match('{^([^<]*)?(</?[^>]+?>)?(.*)$}s',$s,$matches)) {
            print preg_replace($patterns,$replacements,$matches[1]);
            print $matches[2];
            $s = $matches[3];
        }
    }
} else {
    print $s;
}

11.8.4. See Also