Do you know how to extract text from the HTML <body> tag with one regular expression? Here it is:

function extractBody($htmlContent) {
    $result = '';
    $regExp = '/.*<body[^>]*>(.*)<\/body>.*/is';
    if (preg_match($regExp, $htmlContent)) {
        $result = trim(preg_replace($regExp, '\1', $htmlContent));
     }
    return $result;
}

Note that you have to use "i" and "s" modifiers, otherwise this regular expression will not work in all cases. "i" modifier helps to detected <body> tag in mixed or upper case. "s" modifier forces regular expression to work correctly with new line characters.