AS written above, HTML is not a programming language but it is a markup language. With the introduction of HTML 5, the web development is now become more interesting, Developing a perfect front end(design) is not an easy task and for this you must have to learn html. But in case. If you are thinking that you do not want to be a front end developer then you are wrong because if you really wanna be a back-end developer then you must approach for basic knowledge of HTML as it plays a vital role in back end development.With html you should also learn CSS(cascade styling sheet).
CSS stands for cascading style sheet. HTML is not enough, HTML without CSS is like a tea without sugar, For a good design there is a good css code. Css plays a vital role in enhancing the front end design, as simple as you cannot think for a good website without a good hand in CSS. CSS 3 is now loaded with number of predefined functions which makes designing your front end design even more easy. So to be a good front end developer you must have to learn CSS also.
PHP stands for Hypertext Preprocessor . Although PHP is a backend language(runs on server), but with a great flexibility and tech. support PHP is one of the most commonly used language for web development. PHP is an HTML-embedded scripting language used to create dynamic pages quickly.cool thing is that, it is totally open source, you don't have to pay for it.With the advantage of low server maintenance charges and having a huge number of open source libraries php is kicking the web development in an easier way. And in my opinion you should start learning PHP if you are seeking for a developer job.
C# is a product from Microsoft and it is not open source. It comes with an IDE called Visual studio . Doing C# in visual studio saves a lot of time because visual studio is a best editor ever known. Learning C#.net is worthy because in C#, you can make DLL files of your backend code so as to improve your server response time and which is a good thing, it saves the site loading time etc. Like PHP, C# has also a wide range of tech. support but the server maintenance charges are not in favor, and if we talk about the stability, accuracy and reliability of C#, C# is surely winning the race.If you are willing to learn c# then it is suggested that you should learn MVC platform this will make you more eligible for a developer job.
Java is invented by Sun Microsystems in 1990s, it is a class based object oriented programming. Java is one of the most demanding language in todays time and android app development is one the big example for this.But if we talk about java for web development then surely java is lagging behind PHP and C#. For web development you should choose between PHP,C#, Python etc. But building a mobile application java is totally worthy.
Python is a high level, open source server sided scripting language, it can be used for web development as well as mobile app development. More number of developers are now switching to this language because of its flexibility and wide range of application. Python can easily run on LINUX/Windows based servers. Its highly scalable and a good choice for rapid application developmentDoing Python saves a lot of time because there are number of already built applications are available for this language and the only thing remains is to use them. A fewer number of lines of code in Python can do a lot. There is super cool web development framework available in Python called Django, if you are willing to learn this language then you should learn to work with Django framework.
Ruby is a dynamic, object oriented scripting language, like python its also open source and highly scalable. On Ruby you can develop websites as well as mobile based applications. Ruby is known for its simple and easy writable methods. Learning ruby is not enough, you should learn ruby with a framework Ruby on Rails(Rails) this will make interesting to code in Ruby language. Ruby is fairly user-friendly language for beginners like python.