Personally, I always start out by making all my input fields type="text", then I validate and sanitize it with PHP, then I'll do the same with jQuery/Javascript, then finally I will change the input type to the correct version and tag a required tag on it (if it is required of course).
Is it really necessary? Probably not, but I would rather over validate user input then under validate it. Users are tricky, and some of them are still surfing on way old browsers that don't recognize the input type="email" fields.