Web development is the back-end of the website, the programming and interactions on the pages. A web developer focuses on how a site works and how the customers get things done on it. Good web developers know how to program CGI and scripts like PHP. They understand about how web forms work and can keep a site running effectively.
But when you apply for a job or look for someone to work on your site, you need to know what you’re looking for — web design or web development. Even if you can do or hire someone to do both jobs, knowing the difference is key to getting the job done.