iOS does not support Flash. If you want your site to work on mobile devices, replace Flash with HTML5 or at least include an HTML5 fallback to support that ever-growing group of users.
They are harmless, but if you’d like to reduce and clean up your code a bit, you can remove XHTML close tags (” />”) from elements.
This is especially important for mobile devices that show customized keypads and widgets for different types.
If this is a site under development, versus a retired page of content, confirm it is an HTML5 page, using the HTML5 doctype: <!DOCTYPE html>
New HTML5 elements are not recognized by Internet Explorer versions less than 9. These browsers still have a huge market share, and it is highly recommended that you use an HTML5 shim.