Firefox has an "inspect element" (I think that's what it's called, my browser isn't in english) option - probably other browsers as well. The lyrics are in <canvas> tag.
Alternatively it's in page source, but it's in unicode character codes so you'd have to convert it. Dunno if there are tools for that. Google seems to do it, but it gives an error when trying to do it all at once - you might do it piece by piece or whatever.