If you have a background in programming and computer science, are proficient in a similar language, are very good at self-teaching, are already familiar with the web as a platform (how HTML, CSS, JavaScript, browsers, servers, AJAX, and the Document Object Model/DOM work, and work together) then it might be possible to learn JavaScript's syntax, commands, and patterns enough to make something in a week, but I think it would take months of learning at a minimum before somebody would be at a competitive enough level to get hired as a JS programmer. But please feel free to prove me wrong though 😄