Best practice for meta data in a html document?

I work on a large scale, high volume, public facing web application. The successful operation of the application is very important to the business, and so there are a number of MI tools that run against it.

One of these MI tools essentially looks at the html that is sent to the browser for each page request (I've simplified it quite a lot, but for the purpose of this question, its a tool that does some analysis on the html)

For this MI tool to get the data it needs, we put meta data in the head element. Currently we do it as html comments:

<!doctype html>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en" class="">
<head>
    <!-- details = 52:AS6[rxSdsMd4RgYXJgeabsRAVBZ:0406139009] -->
    <!-- policy id = 1234567890 -->
    <!-- party id = 0987654321 -->
    <!-- email address = [email protected] -->
    <!-- error = 49 -->
    <!-- subsessionid = bffd5bc0-a03e-42e5-a531-50529dae57e3-->
    ...

And the tool simply looks for a given meta data comment with a regex

As this data is meta data, I'd like to change it to html meta tags because it feels semantically correct. Something like this:

<!doctype html>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en" class="">
<head>
    <meta name="details" content="52:AS6[rxSdsMd4RgYXJgeabsRAVBZ:0406139009]" />
    <meta name="policyId" content="1234567890" />
    <meta name="partyId" content="0987654321" />
    <meta name="emailAddress" content="[email protected]" />
    <meta name="error" content="49" />
    <meta name="subsessionid" content="bffd5bc0-a03e-42e5-a531-50529dae57e3" />
    ...

This feels more semantic, and I can get the MI tool to work with it no problem - just a case of changing the regexes. However it now gives me a problem with the w3c validator. It wont validate because the meta names I'm using are not recognised. I get the error "Bad value details for attribute name on element meta: Keyword details is not registered." and it suggests I register these name values on the WHATWG wiki.

Whilst I could do this it doesn't feel right. Some of my meta tags are 'generic' (such as error and emailAddress) so I could probably find an already registered name value and use that. However, most of them are industry/organisation specific. It feels wrong to register a public name value called subsessionid or partyId as these are specific to my organisation and the application.

So, the question is - what is considered best practice in this case? Should I leave them as html comments? Should I use meta tags as above and not worry that w3c validation fails? (though that is increasingly important to the organisation) Should I attempt to register my meta name values on WHATWG wiki, but knowing they are not very generic? Or is there another solution?

Appreciate your thoughts, cheers

Nathan

Edited to show the the final solution:

The full answer I'm going with is as follows. Its based on Rich Bradshaws answer, so his is the accepted one, but this is what I'm going with for completeness:

<!doctype html>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en" class="">
<head>
    <meta name="application-name" content="Our app name" 
        data-details="52:AS6[rxSdsMd4RgYXJgeabsRAVBZ:0406139009]" 
        data-policyId="1234567890"
        data-partyId="0987654321"
        data-emailAddress="[email protected]"
        data-error="49"
        data-subsessionid="bffd5bc0-a03e-42e5-a531-50529dae57e3"
    />
    ...

This validates, so all boxes ticked :)

W3C validation is meaningless. HTML != XML, so there isn't any schema to validate it. No browser will choke because you added a meta element with an unregistered name. If you really are worried, you could use the data attribute on a meta element like:

<meta data-details="52:AS6[rxSdsMd4RgYXJgeabsRAVBZ:0406139009]" data-policyId="0123456789" />

at least then you know no future spec will give meaning to your data.

For more info read: http://www.whatwg.org/specs/web-apps/current-work/multipage/elements.html#custom-data-attribute

While your example may work, note that the keyword application-name is for Web applications only.

For usual webpages not being web applications, or if no application-name shall be given, see some alternatives:

Using `data-*` attributes in the `head`

No need for a meta element.

<!DOCTYPE html>
<html>
<head
    data-details="52:AS6[rxSdsMd4RgYXJgeabsRAVBZ:0406139009]" 
    data-policyId="1234567890"
    data-partyId="0987654321"
    data-emailAddress="[email protected]"
    data-error="49"
    data-subsessionid="bffd5bc0-a03e-42e5-a531-50529dae57e3">
</head>

Using Microdata

You could create a vocabulary, but that’s not required for local use.

<!DOCTYPE html>
<html>
<head itemscope>
  <meta itemprop="details" content="52:AS6[rxSdsMd4RgYXJgeabsRAVBZ:0406139009]" />
  <meta itemprop="policyId" content="1234567890" />
  <meta itemprop="partyId" content="0987654321" />
  <link itemprop="emailAddress" href="mailto:[email protected]" /> <!-- or use a meta element if you don’t want to provide a full URI with "mailto:" scheme -->
  <meta itemprop="error" content="49" />
  <meta itemprop="subsessionid" content="bffd5bc0-a03e-42e5-a531-50529dae57e3" />
</head>

Using data in a `script`

The script element can be used for data blocks. You can choose any format that suits your needs. Example with plain text:

<!DOCTYPE html>
<html>
<head>
  <script type="text/plain">
    details = 52:AS6[rxSdsMd4RgYXJgeabsRAVBZ:0406139009]
    policyId = 1234567890
    partyId = 0987654321
    emailAddress = [email protected]
    error = 49
    subsessionid = bffd5bc0-a03e-42e5-a531-50529dae57e3
  </script>
</head>

Best practice for meta data in a html document?

Using `data-*` attributes in the `head`

Using Microdata

Using data in a `script`

Related

Recent Posts

Best practice for meta data in a html document?

Using data-* attributes in the head

Using Microdata

Using data in a script

Related

Recent Posts

Using `data-*` attributes in the `head`

Using data in a `script`