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So let's get started with this course and with everything you need to know about Javascript by diving

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into this important question, what is Javascript?

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Let's have a look at a couple of definitions.

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Javascript is a dynamic, weakly typed programming language which is compiled at runtime.

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It can be executed as part of a web page in a browser or directly on any machine in a so-called host

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environment.

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Okay, not entirely clear yet,

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let's have a look at an additional definition.

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Javascript was created to make web pages more dynamic,

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that's kind of the idea why Javascript was invented in the past you could say, more about the history

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of Javascript in a second by the way.

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So it was invented to change the content on a page directly from inside the browser

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and originally, it was called LiveScript but due to the popularity of Java back at the time, it was renamed

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to Javascript to resemble Java by its name.

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Javascript however is totally independent from Java,

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that's important to understand and has nothing in common,

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it really was just named Javascript because Java was popular and people who invented Javascript

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wanted Javascript to be a thing I guess but I'm not sure, are these definitions really clear?

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Do you now know what Javascript is?

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Does dynamic, weakly typed compiled at runtime make web pages more dynamic?

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Does this tell you something?

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Well let's take a step back maybe,

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how do web pages work? You are the user visiting a web page and when you do visit a web page, you use

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browser for that. You use your client, your machine, your laptop, your computer, where you have a browser

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installed on it,

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you enter a URL or click on a search result on Google and the web page gets loaded,

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To be precise when you initially visit a web page, a request is sent to the server,

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so to a computer in the Internet where that web page, where the HTML file is hosted and that server

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then loads that web page and sends it back to your browser in a so-called response and the most basic

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form of response we know or we typically see and use when we work with the Internet,

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when we visit a page is simply an HTML page which is sent back by the server to the client.

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Now let's say on that loaded web page, let's say it's an online shop,

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doesn't really matter,

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the user clicks a button to submit a form, for example to order some products.

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Now this will then trigger a new request which is sent by the browser to the server to send this form

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submission to the server and the server will handle the incoming request,

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maybe store some order data in a database and once it's done, it will reply back with a new response,

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with a new web page, a new HTML document which is sent back to the client, maybe the order confirmation

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page. So this is how we interact with the web,

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this is how web pages traditionally work.

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Now Javascript helps us make this more reactive,

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it helps us make a web page more reactive and skip that second request response flow in some circumstances

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to instead change the already loaded page and do something there.