这个可是好东西，以后大家可能会用上哦：HTML to XHTML Converter_PHP教程

xhtml

<?

if (!empty($type)) {
    if ($type == "path") {
        if (!empty($path)) {
            if (file_exists($path) && is_file($path)) {
                $file = file($path);
                if (substr($file[0],0,9) != "<!DOCTYPE") $doctype=0;
                    $file = join('', $file);
                } else {
                    die ("No such file.");
                }
            } else {
                die ("No file specified.");
            }
        } elseif ($type == "file") {
            if (!empty($file)) {

            } else {
                die ("No file specified.");
            }
    } else {
        die ("No file specified.");
    }

# specify html file, check for doctype
//$file = file("file.html");
//if (substr($file[0],0,9) != "<!DOCTYPE") $doctype=1;
//$file = join('', $file);

# make tags and properties lower case, close empty elements, quote all properties
$search  = array ("'(<//?)(/w+)([^>]*>)'e",
                   "'(<//?)(br|input|meta|link|img)([^>]*)( />)'ie",
                   "'(<//?)(br|input|meta|link|img)([^>]*)(/>)'ie",
                   "'(<//?)(br|input|meta|link|img)([^>]*)(>)'ie",
                   "'(/w+=)(/w+)'ie",
                   "'(/w+=)(.+?)'ie");
$replace = array ("'//1'.strtolower('//2').'//3'",
                   "'//1//2//3>'",
                   "'//1//2//3>'",
                   "'//1//2//3 ///4'",
                   "strtolower('//1').'/"//2/"'",
                   "strtolower('//1').'//2'");
$file = preg_replace($search, $replace, $file);

# return xhtml-compliant document
echo "<textarea cols=/"100/" rows=/"20/">";
if (isset($doctype)) echo '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "DTD/xhtml1-transitional.dtd">'."/n";
echo stripslashes(stripslashes(stripslashes($file)));
echo "</textarea>";

} else {
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "DTD/xhtml1-transitional.dtd">
<head><title>HTML -> XHTML Convertor</title></head>

<body>


<form action="<?=$PHP_SELF?>" method="get">
<input type="hidden" name="type" value="path" />
<font face="verdana">File path:</font> <input type="text" name="path" size="50" />
<input type="submit" value="Submit" />
</form>

<b><font face="verdana">OR</font></b><br /><br />

<form action="<?=$PHP_SELF?>" method="get">
<input type="hidden" name="type" value="file" />
<font face="verdana">File contents:</font><br />
<textarea name="file" rows="10" cols="50"></textarea><br />
<input type="submit" value="Submit" />
</form>

</body>

</html>
<?
}
?>
原文自www.evilwalrus.com

这个可是好东西，以后大家可能会用上哦：HTML to XHTML Converter_PHP教程_编程技术