javascript – Heaplevel AB https://heaplevel.com Software Development Partner Thu, 25 Jul 2019 17:12:13 +0000 en-US hourly 1 https://wordpress.org/?v=7.1 https://heaplevel.com/wp-content/uploads/2020/01/cropped-Heaplevel-1-32x32.png javascript – Heaplevel AB https://heaplevel.com 32 32 Getting started with Javascript https://heaplevel.com/blog/getting-started-with-javascript/ Thu, 25 Jul 2019 16:59:46 +0000 https://heaplevel.com/?p=75 If you want to start programming in Javascript you might ask where do you actually start? It might be that you’ve been interested in learning more about web programming in general, for which it would be useful to also learn about HTML and CSS as well. While HTML and CSS deal with the structure of …

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]]> If you want to start programming in Javascript you might ask where do you actually start?

It might be that you’ve been interested in learning more about web programming in general, for which it would be useful to also learn about HTML and CSS as well. While HTML and CSS deal with the structure of a website, Javascript adds the dynamic flavour to your website.

There is also a possibility that you want to learn Javascript to write backend applications, using NodeJS. The applications for Javascript are several, both websites and web applications can use Javascript.

If this is the first time to Javascript you can start by learning about the language itself and start play around in a sandbox environment. That is the best option to learn Javascript.

Learn Javascript by examples

We will experiment with Javascript by looking at some examples. This guide is for you that have a little programming background.

  1. Navigate to JSFiddle
  2. Copy the following code in the HTML box
  3. Hit the Run button. You should see a popup displaying the text “Hello, world!”
<!DOCTYPE HTML>
<html>
<head>
<script>
    alert( 'Hello, world!' );
  </script>
</head>
<body>
  The body
</body>

</html>

So what did we actually do here? Simply explained we used the Javascript function called alert to write a message in a popup box.

Go ahead and create a second alert with a new message. After you hit Run you should have two popup boxes with two different messages.

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]]> Javascript true and false values https://heaplevel.com/blog/javascript-true-and-false-values/ Thu, 23 May 2019 09:34:40 +0000 https://heaplevel.com/?p=41 In Javascript comparing values are not always as straightforward as one would expect. Overcoming that fear of which variables are truthy are sometimes is just as easy as learning which values are falsy. If you remember them (6 values) then you can easily know which values are true. NaN false undefined ”, “”, “ – …

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]]> In Javascript comparing values are not always as straightforward as one would expect. Overcoming that fear of which variables are truthy are sometimes is just as easy as learning which values are falsy. If you remember them (6 values) then you can easily know which values are true.

  • NaN
  • false
  • undefined
  • ”, “”, “ – the empty string either single quotes, double quotes or template literalts
  • 0
  • null

How do you remember these 6 falsy values in Javascript you say? People remember things differently and since all are unique there are many ways to remember.

Remember the simple things first, the one number i.e 0 (zero) is always false. That’s easy to remember right? Also false makes perfect sense to be…you guessed it: false.

So four values to go, look at this: null, NaN, undefined

Finally strings contain text, strings talk, but a string that doesn’t contain anything can’t talk, so it should be false.

The perfect order

  • 0
  • false
  • null – NaN – undefined — becomes nullnandefined – null (and) undefined. Those are three values coerced into one to remember easily!
  • empty strings – can’t talk, should be false then. ”, “”, “

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]]> Java or Javascript https://heaplevel.com/blog/java-or-javascript/ Tue, 07 May 2019 09:30:56 +0000 https://heaplevel.com/?p=10 What is the difference between Java and Javascript? This confusion is very common and just because they share the same prefix Java it is easy to think they are somehow related. Java is a general programming language used heavily today for writing applications designed to run on desktops or servers. Although Java applications can be …

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]]> What is the difference between Java and Javascript?

This confusion is very common and just because they share the same prefix Java it is easy to think they are somehow related.

Java is a general programming language used heavily today for writing applications designed to run on desktops or servers. Although Java applications can be found in many areas, today many web applications are written with Java as the backend part.

Javascript is a programming language used heavily in web applications too, but found mostly at the frontend part. Although technologies like NodeJS allow you to write server-applications with Javascript. Usually there is a distinction between ‘server Javascript’ and ‘in-browser Javascript’. The important thing to remember is they’re still Javascript but for two different purposes.

In-browser Javascript

Here are some examples of what in-browser JavaScript is used for. Remember all is related to websites.

  • Add or modify the HTML content of a page.
  • Add or modify styles and visual aspects of a page.
  • Add or modify behaviour, i.e what happens when a user clicks a button, text or anything else on the website.
  • Examples of behaviour are also tracking mouse clicks and mouse movement. Even a keyboard press is possible to detect.
  • Network related tasks like connecting to other server for fetching content.
  • Manage those cute little cookies the browser stores
  • Manage the data on the client-side, i.e. the browser.

Server Javascript

The applications with server Javascript are several. This is more related to system functionality as this type of Javascript is executed ‘near the server’. I.e. it is not concerned with the website of a user. But more about operating system related tasks. Examples of this would be

  • Managing files on the hard drive
  • Network handling
  • Security of a server

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