I don't imagine most shops are going to want to pay you for time spent learning, so what to do?
Look at sites, see what they're doing, then try to write something similar yourself. This could take some time.
Maybe you could get some kind of "internship" arrangement. i.e. you work for free in exchange for the learning experience.
IMHO it would be best to be honest about your skill level, it won't do much good to get a job only to lose it if you can't meet their expectations.
If you're good with HTML5, CSS3, (responsive web design too?) show them some of your work as that could help you get your foot in the door.