JavaScript Debugging

Searching for bugs and fixing them is called code debugging.

The bugs might be difficult to diagnose and therefore it is important to have a good approach to find and fix the bugs effectively.


Syntax Error Or Logical Error

Bugs in the code might be syntax errors or logical errors.

Sometimes nothing happens when the code contains bugs and there is few indications where to search.


Developer Tool

Modern web browser includes a powerful suite of developer tools. The tools do a range of things, from inspecting currently-loaded HTML, CSS and JavaScript to showing which assets the page has requested and how long they took to load.

The Developer Tool is enabled pressing F12 or Ctrl + Shift + I.


Check out developer-tools to enhance your productivity

The console.log Method

Use the console.log() method to write log to the debugger window that is visible in Developer Tool.

JS JavaScript - The console.log Method

<!DOCTYPE html>
<html>
<body>
 
<h1>Debugging my Page</h1>
 
<script>
var x = "This is my debugging text: ";
var y = 100;
var output = x + y;
console.log(output);
</script>
 
</body>
</html>

The console.table Method

Use the console.table() method to write complex set of objects to the debugger window.

JS JavaScript - The console.table Method

var cars = [
{ car: 'Tesla', model: 'Model X', range: 510 },
{ car: 'Byton', model: 'K-Byte', range: 400 },
{ car: 'Audi', model: 'e-tron', range: 400 },
{ car: 'Mercedes', model: 'EQ', range: 410 }
];
 
console.table(cars);

Available console Methods

Differentiate the log with using the many console methods that are available:
console.log, console.debug, console.warn, console.info, console.error.


The debugger Keyword

The debugger keyword stops the execution of JavaScript.

The debugger has the same function as setting a breakpoint.

The debugger statement has no effect if debugging is not available.

JS JavaScript - The debugger Keyword

var x = "This is my debug-text";
var y = "This text is visible after debugger breakpoint";
 
document.getElementById("message").innerHTML = x;
debugger;
document.getElementById("message").innerHTML = y;

Breakpoints

It is possible to set breakpoints in the JavaScript code in the debugger window.

JavaScript will stop executing at each breakpoint, then it is possible to examine the JavaScript values.

It is possible to resume the execution of code after examining the values.


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Check this out

JS JavaScript: Switch

The switch statement evaluates an expression and match the expression's value to a case clause.

A switch statement can replace multiple if checks.
It gives a more descriptive way to compare a value with multiple variants.

JS JavaScript: Let

Let is a keyword that is used to declare a variable.

You should use let instead of var when declaring a variable.

One of the most important things is that you should try to keep things simple!<....

JS JavaScript: Developer Tools

Developer Tools are tools that are a part of most modern web browsers.

Every Web Developer should know how to use the tools. The tools do a range of things, from inspecting currently-loaded HTML, CSS and JavaScript to showing which assets the page has requested and how long they took to l....

JS JavaScript: Errors

There will be errors in the code. It is good practice to handle exceptions/errors.

Exceptions are a type of error that occurs during the execution of an application. Errors should be logged. Sometimes it is possible to recover a bug and proceed.
Other cases the user should get inform....


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JavaScript is one of the 3 core language technologies of the World Wide Web that all web developers must learn:

1.      HTML to define the content of web pages.

2.      CSS to specify the layout of web pages.

3.      JavaScript to program the behavior of web pages.

JavaScript is a scripting or programming language that allows you to implement complex things on web pages. Every time a web page does more than just sit there and display static information for you to look at, displaying timely content updates, interactive maps, animated 2D/3D graphics, scrolling video jukeboxes, etc. − you can bet that JavaScript is probably involved.


The benefits of using JavaScript are:

1.      You can validate user input before sending the page off to the server. This saves server traffic, which means less load on your server.

2.      Immediate feedback to the visitors − They don't have to wait for a page reload to see if they have forgotten to enter something.

3.      Increased interactivity − You can create interfaces that react when the user hovers over them with a mouse or activates them via the keyboard.

4.      Richer interfaces − You can use JavaScript to include such items as drag-and-drop components and sliders to give a Rich Interface to your site visitors.


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Need more Honney

NDC Conferences

The NDC Conferences (Norwegian Developers Conference) are one of the world`s largest independent software conferences for .NET & Agile development. The conference covers everything you need to know within software development. The conferences are held each year in many places such as Oslo, Copenhagen, London, Sydney and Minnesota.

Update Conference Prague

Update Conference Prague is the biggest developer conference in the Czech Republic. The conference is offering sessions delivered by the top experts from all around the world. Their goal is to inspire the attendees and enrich their knowledge.

Troy Hunt

Learn about Web Security from Troy Hunt. He is a really engaged speaker that frequently give talks on conferences around the world. Troy is a Microsoft MVP and you can even learn from him on some great courses on Pluralsight.

W3Schools

W3Schools.com is a great education Web Site for learning web technologies. On W3Schools you may find well organized basic to advanced tutorials and references.

Scott Hanselman

Learn about Web Technologies and new trends from Scott Hanselman. Scott Hanselman is an author of developer books and he is an engaged speaker that usually talks about the Microsoft stack. You may meet Scott on conferences around the world.

Developer Week

DeveloperWeek is one of the world’s largest developer conferences. Developer Week focus on new dev technologies, the conference have talks and workshops for newbies and experienced audience. You can attend on a Developer Week conference different places in Nothern America.


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Learn JavaScript Debugging

Searching for bugs and fixing them is called code debugging. The bugs might be difficult to diagnose and therefore it is important to have a good approach to find and fix the bugs effectively. Bugs in the code might be syntax errors or logical errors. Sometimes nothing happens when the code contains bugs and there is few indications where to search. Modern web browser includes a powerful suite of developer tools. The tools do a range of things...

Explore JavaScript Arrays

Arrays are frequently used by developers. Programming languages can have slightly different implementation of arrays. An array is an object that can store a collection of items. You may say it`s a special variable that can have more than one value. The array holds many values under a single name, and you may access the values by referring to an index number. The easiest way to create....

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It is essential to give the user a good user experience. There are many things you should focus on, one of them is how you use colors on your website. We don't have to struggle with black and white TVs anymore. Users expect more and more and we can apply colors to everything we want. Texts, borders, backgrounds, shadows – in HTML they all can have whatever color you decide....

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