How can i render and work with custom HTML tags like <g:plusone />?

I see google is using its custom tag and i know google is using javascript to render iframe instead of this tag, it开发者_StackOverflow中文版 is intresting and i want to know how can i have my own custom tag using javascript?

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You've been able to have custom tags for awhile by namespacing the XML in your doctype. For example, facebook does it like this:

    xmlns:fb="http://www.facebook.com/2008/fbml"

Beware though, IMO custom tags are a BAD idea. It defeats the whole purpose of having standards and can wreak havoc on maintenance. Make sure you really weigh the pros and cons before going this route.