(This is similar to the (also unanswered) question #3430506, but applies to input tags instead of HTML5 elements.)
On buttons, th
I ran into this bug today when my mom told me that a page I had made was missing text on her old iPhone 3G. Sure enough, I fired up my wife's old 3G we have lying in a drawer someplace, and the text on one of my buttons is being pushed off to the side because Safari is inserting some giant spacing.
The good news is that in the latest update (don't know exactly what, but I've got an updated iPhone 4), this bug has been fixed.
Bad news is that if users don't update their browsers, I can't find any way around it outside of just not using the tag.
My advice for right now is to check the version of Mobile Safari. If they're running the latest version (or whichever version fixed this bug or higher), they get the page with the button. If not, they can get served a page with alternate tags used to make the buttons. On my page this doesn't look as nice, and it's a little awkward, but I'm already checking browsers based on mobile or desktop versions of the site, so this isn't too much on top of that.
Hope this helps.