How do I re-enable zoom on mobile websites that disable it?

Question

Many mobile-optimized websites disable zooming using the viewport meta tag. I'd like a way to re-enable zooming on such sites.

Answer 1

In lieu of a better solution, I wrote a bookmarklet to re-enable zooming.
It seems to work in the Android Browser at least.

javascript: document.querySelector('meta[name=viewport]').content = 'width=device-width; initial-scale=1.0; maximum-scale=3.0; user-scalable=1;'; void(0);