<?php
    use Symfony\Component\CssSelector\CssSelector;

    // require Composer AutoLoader
    require __DIR__ . '/vendor/autoload.php';

    $selector = CssSelector::toXPath('a#outlook');
    $dom = new DOMDocument;
    $dom->loadHTML(file_get_contents(__DIR__ . '/html'));
    $finder = new DOMXPath($dom);
    foreach ($finder->evaluate($selector) as $item) {
        $item->setAttribute('href', 'http://google.com/');
    }
    echo $dom->saveHTML();