Devoting 12 hours a day, 7 days a week, in how many days can a person learn to be web developer ?

This would very a ton from person to person. You might fly through one part and another might take days to click. Something I find easy could be an enormous struggle for you or vice versa.

It also depends on what kind of developer you want to be and how good you want to be at it. I would say with that much time on your hands to practice it would be possible in 3-6 months. There is a lot to learn! In 1 month with that kind of work you could probably accomplish basic things slowly but well. The next few month would be advancing and getting up to "speed" in the industry. There is a lot to learn from languages to frameworks to API's. At that point you would be about the level of a Junior Developer in your chosen field. This is when I would really start to flesh out a portfolio.

I would recommend 6 months just to make sure you truly absorb all the content but if you donated all 12 hours of your allotted time to learning studying and practicing you might be able to do it sooner.

Goodluck! --Ricky

I've seen hack schools that claim that 98% of their graduates find a job after finishing their 3 months course, so my guess is that it's doable in a short amount of time if you put in the work. I've been spending most of my free time learning on treehouse and my hope is that by this summer I'll be good enough to start freelancing, and use what I produce from that to land a job as a junior developer somewhere.

Ricky & Var, Thanks a lot for your input. Appreciate that. Regards.