PHP DOMDocument errors/warnings on html5-tags

122
votes

I've been attempting to parse HTML5-code so I can set attributes/values within the code, but it seems DOMDocument(PHP5.3) doesn't support tags like <nav> and <section>.

Is there any way to parse this as HTML in PHP and manipulate the code?

Code to reproduce:

<?php
$dom = new DOMDocument();
$dom->loadHTML("<!DOCTYPE HTML>
<html><head><title>test</title></head>
<body>
<nav>
  <ul>
    <li>first
    <li>second
  </ul>
</nav>
<section>
  ...
</section>
</body>
</html>");

Error

Warning: DOMDocument::loadHTML(): Tag nav invalid in Entity, line: 4 in /home/wbkrnl/public_html/new-mvc/1.php on line 17

Warning: DOMDocument::loadHTML(): Tag section invalid in Entity, line: 10 in /home/wbkrnl/public_html/new-mvc/1.php on line 17

6
phphtmldomdocument
Ops, for me loadHTML($HTML5) returns FALSE (failure)! I need to change the new tags to DIVs... It is not only a problem of "warnings" on my screen. – Peter Krauss
This issue had been reported for PHP at bugs.php.net/bug.php?id=60021 which in turn spawned a feature request in the underlying libxml2: bugzilla.gnome.org/show_bug.cgi?id=761534 – cweiske

6 Answers

217
votes

No, there is no way of specifying a particular doctype to use, or to modify the requirements of the existing one.

Your best workable solution is going to be to disable error reporting with libxml_use_internal_errors:

$dom = new DOMDocument;
libxml_use_internal_errors(true);
$dom->loadHTML('...');
libxml_clear_errors();
14
votes

You could also do

@$dom->loadHTML($htmlString);
9
votes

You can filter the errors you get from the parser. As per other answers here, turn off error reporting to the screen, and then iterate through the errors and only show the ones you want:

libxml_use_internal_errors(TRUE);
// Do your load here
$errors = libxml_get_errors();

foreach ($errors as $error)
{
    /* @var $error LibXMLError */
}

Here is a print_r() of a single error:

LibXMLError Object
(
    [level] => 2
    [code] => 801
    [column] => 17
    [message] => Tag section invalid

    [file] => 
    [line] => 39
)

By matching on the message and/or the code, these can be filtered out quite easily.

4
votes

There doesn't seem to be a way to kill warnings but not errors. PHP has constants that are supposed to do this, but they don't seem to work. Here is what is SHOULD work, but doesn't because (bug?)....

 $doc=new DOMDocument();
 $doc->loadHTML("<tagthatdoesnotexist><h1>Hi</h1></tagthatdoesnotexist>", LIBXML_NOWARNING );
 echo $doc->saveHTML();

http://php.net/manual/en/libxml.constants.php

-1
votes

This worked for me:

$html = file_get_contents($url);

$search = array("<header>", "</header>", "<nav>", "</nav>", "<section>", "</section>");
$replace = array("<div>", "</div>","<div>", "</div>", "<div>", "</div>");
$html = str_replace($search, $replace, $html);

$dom = new DOMDocument();
$dom->loadHTML($html);

If you need the header tag, change the header with a div tag and use an id. For instance:

$search = array("<header>", "</header>");
$replace = array("<div id='header1'>", "</div>");

It's not the best solution but depending on the situation it can be useful.

Good luck.

-6
votes

HTML5 tags almost always use attributes such as id, class and so on. So the code for replacing will be:

$html = file_get_contents($url);
$search = array(
    "<header", "</header>", 
    "<nav", "</nav>", 
    "<section", "</section>",
    "<article", "</article>",
    "<footer", "</footer>",
    "<aside", "</aside>",
    "<noindex", "</noindex>",
);
$replace = array(
    "<div", "</div>",
    "<div", "</div>", 
    "<div", "</div>",
    "<div", "</div>",
    "<div", "</div>",
    "<div", "</div>",
    "<div", "</div>",
);
$html = str_replace($search, $replace, $html);
$dom = new DOMDocument();
$dom->loadHTML($html);