Yes, this is actually the recommended practice from the documentation. Built-in Angular directives are typically prefixed with `ng-`, and they suggest that other projects/developers use their own prefixes to avoid conflict.
Why not use XHTML at that point? If XHTML ever had a clear mission statement in life it was that.
I mean I thought XHTML was a curse a few years ago when it was The Thing Every Good Designer Uses™ since it couldn't be rendered as XML in the most popular browser. But hopefully that's not as much an issue anymore. Or maybe it is. I haven't kept up with IE.
Or you know, an adoption of only the needed part, instead of all the BS junk that comes with XML namespaces.
>Why not use XHTML at that point?
Because of all the other junk that comes with it. And because it comes from W3C.