HTML is markup for formatting the page. It is not really a programming language, it is more like advanced punctuation. CSS is rulesets for telling the browser how to display the HTML formatted content. It is also not a programming language in the same way HTML is, although it can be a lot more powerful.
JavaScript is a programming language. You use it to make the website interactive. Get Firebug or a similar add-on for Firefox, or just right click and 'Inspect Element' in Chrome to see the JavaScript for more detail on what JavaScript does.
AJAX is an extension of JavaScript to get data from the webserver and update the page with it, w
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HTML is markup for formatting the page. It is not really a programming language, it is more like advanced punctuation. CSS is rulesets for telling the browser how to display the HTML formatted content. It is also not a programming language in the same way HTML is, although it can be a lot more powerful.
JavaScript is a programming language. You use it to make the website interactive. Get Firebug or a similar add-on for Firefox, or just right click and 'Inspect Element' in Chrome to see the JavaScript for more detail on what JavaScript does.
AJAX is an extension of JavaScript to get data from the webserver and update the page with it, without having to refresh the page.
PHP is code commonly used server side to interact with the filesystem and databases and output HTML. You can also use python, Perl, .NET and a handful of other languages/frameworks to do this.
MySQL is a database. You should learn how to use it. You are going to have to learn HTML, CSS, JavaScript and one of PHP, Python, Perl, or related frameworks (or other possibilities that I am not aware of). Later, you can concern yourself with certain JavaScript frameworks, especially query, but there is also prototype and a few others.
In finding an answer for your question 'what are the best web programming languages?' you should investigate PHP, Python, Perl, or frameworks (Ruby on Rails, CakePHP, Django, etc.). There are a bunch of questions relating to these already on Quora, and a ton of information elsewhere on the internet. [I've only worked with PHP for this task, so I might have left out something important about using the other languages/frameworks for outputting HTML].
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