JavaScript Keyword This


The keyword This

In JavaScript the execution context for an execution is by default global. That means that when this is used in a function it refers to the owner of the function, that is in the object where it exists. I JavaScript there are some differences between strict mode and non-strict  mode and mostly  the value of this is determined by how a function is called. 


The value this cannot be set by assignment during execution and the value can be different every time the function is called.


The expression this

JS JavaScript - The expression this

var aThisTest = {
    prop: 66,
    func: function () {
    return aThisTest.prop;
},
};
 
alert(aThisTest.func());
// Output: 66

This expression in a global context

When we are operating in a global execution context (not inside any function), this refers to the global object both in strict and none-strict.

JS JavaScript - This expression in a global context

// In a web browser the global object is the same as the window object.
alert(this === window); // Result: true
 
count = 99;
alert(window.count); // Result: 99
 
this.testString = "Honneybag";
alert(window.testString )  // Result: "Honneybag"
alert(testString )                // Result: "Honneybag"

Learn more about JavaScript Scope

This expression in a function context - none strict mode

When the value of this isn't set by the call and the code is in none-strict mode, this is by default set the global object. The global object in this context is the window in a browser.

JS JavaScript - The expression this - none strict mode

function TestThisFunction() {
    return this;
}
 
TestThisFunction() === window; // true: the result in a browswer
TestThisFunction() === global; // true: the result in node


This expression in a function context - strict mode

When using the value of this in strict mode it stays the same as it was set to, when entering the execution context. Therefore in this example this will be undefined.

JS JavaScript - The expression this - strict mode

function TestThisFunction() {
'use strict'; // see strict mode
    return this;
}
 
TestThisFunction() === undefined; // true

BACK TO TOP






Check this out

JS JavaScript: Comments

JavaScript comments can be used to to explain and make the code more readable. JavaScript comments can also prevent execution of code.

It is possible to comment code as a single-line comment or as a multi-line comment.

JS JavaScript: Events

Events are actions or occurrences that happen to HTML elements.

JavaScript can act when an HTML Event occurs.

Events can represent everything from basic user interactions to automated notifications of things happening in the rendering model.

JS JavaScript: Numbers Methods

Number methods can help you when working with number datatypes. The number methods are improved in ES6 (ECMAScript 6).

Keep reading to understand how the number methods and properties may help you.

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!<....


BACK TO TOP

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.


BACK TO TOP

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.


BACK TO TOP

Honneybag blog



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....

Ultimate Guide to HTML Colors

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....

Wanna be a sheep? Check out the most popular subjects
HONNEYBAG BLOG
HONNEYBAGBLOG INSPIRE-AND-BE-INSPIRED
JAVASCRIPT ESSENTIALS
HTML FORMATTING
HONNEYBAGBLOG EXPLORE-JAVASCRIPT-ARRAYS
Wanna be a little different? Check out the less popular subjects
HTML INTRODUCTION
HTML ESSENTIALS
JAVASCRIPT BREAKER
HTML COMMENTS
HTML BUILDING-BLOCKS
BACK TO TOP