Is there a way to add the date/time of generation in the xml sitemap?

Normally they will be added automaically.

See this help entry on dates information in XML sitemaps:
http://www.microsystools.com/products/sitemap-generator/help/http-last-modified-meta/

Thanks for your reply, but this refers to the field "last modified". I want to add a date/time in the header, perhaps something like this: <!-- Last Update of Sitemap 2013-01-31T11:48:15+3:00 --> or maybe there is another way?

Hi,

Google and other search engines will automatically be able to see when your XML sitemap itself was last updated. (They retrieve last-modified HTP header on it.) You can check this yourself by open your http://example.com/sitemap.xml file in e.g. FireFox with Live HTTP Headers plugin or similar.

The only time you can add such information in XML sitemap protocol standard is in sitemap index file:
http://www.sitemaps.org/protocol.html#index

Quote

Code Select Expand


<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
   <sitemap>
      <loc>http://www.example.com/sitemap1.xml.gz</loc>
      <lastmod>2004-10-01T18:23:17+00:00</lastmod>


However, you can't add it for the XML sitemap file inside the XML sitemap file itself. (Inside the XML sitemap file you can only last modified / updated information for the URLs listed in it.)

I downloaded the extension (for Chrome) and can now see exactly what I wanted without any additional effort - Great support - Thanks

Glad to hear!