This article is not about the negative aspects of HTML but about that other dark side of HTML that is called shadow DOM . If you are a frontend developer and you have never heard about shadow DOM then you should definitely keep reading because you are missing some cool stuff about webdevelopment.
Today I spoke with a frontend developer at my work and he showed me some really nice tools frontend developers use nowadays for creating websites. As a backend developer I never looked further then Twitter Bootstrap and jQuery but frontend development is so much more I discovered today!
Ajax requests are only possible when the protocol, domain and port number are the same. But sometimes you want to do Ajax calls to a different domain for example when you are creating a shared service that people should be able to call using Ajax or when you are developing locally and you are testing on a remote server. There are multiple ways to get around this restriction for example by using CORS, an iFrame or JSONP. In my last project I got around the restriction using JSONP, so I will explain that here. See links for more information about solving it using CORS.