What are the development technologies for web front-end? What to master in web front-end development front-end technology

What are the development technologies for web front-end? What to master in web front-end development

With the in-depth development of the Internet, Web front-end development is now very popular, which is also a technology required by every company, and also a popular profession in recent years. With the popularity of JS and XHTML applications, Web front-end technology is gradually known by the public and learned by many people. So w
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