Don't do this for web development. The browser emulations are just that, emulations, and they fail to be perfect emulations.
Which means you are likely to be fixing rendering issues and buggy behaviour in the emulated version that don't exist on the real thing, and more importantly missing issues that are evident in the real browser but not on the emulation.
It's a cognitive dissonance, you are testing a browser stack your customers won't be using.
Virtual machines are practically a better solution, though it gets into slighty murky territory when there's a lot of JavaScript magic going on. At that point, nothing really beats a native browser running on native hardware.
Which means you are likely to be fixing rendering issues and buggy behaviour in the emulated version that don't exist on the real thing, and more importantly missing issues that are evident in the real browser but not on the emulation.
It's a cognitive dissonance, you are testing a browser stack your customers won't be using.
Virtual machines are practically a better solution, though it gets into slighty murky territory when there's a lot of JavaScript magic going on. At that point, nothing really beats a native browser running on native hardware.