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  Some short code snippets which use all JavaScript keywords

In JavaScript, keywords are reserved and cannot be used as variable or function names. For example void, function and this are JavaScript keywords, they are keywords which are reserved for special use. Here is list of the keywords in JavaScript. We also show you some short code snippets which use all the keywords in JavaScript.void function() {//abcd   do break;while(typeof delete this);  for(var a;;)  if (true)  with(null)  try{}catch(a){}finally{} else throw new 1;&nbs...

   Code snippet,JavaScript,keyword     2012-07-16 12:12:05

  Why 0.1+0.2 != 0.3

In programming languages such as JavaScript, c/c++, Java and Matlab, you will find that you will get unexpected result when doing float point calculation. For example, when calculating 0.1 + 0.1, you will not get 0.3: > 0.1 + 0.2 == 0.3 false > 0.1 + 0.2 0.30000000000000004 Don't be surprised of this result, this is the end result of IEEE 754 standard, float point number cannot be accurately represented according to IEEE 754 because: No enough memory is allocated for representing the num...

   float point,comparison,JavaScript     2014-11-19 05:32:46

  Which one has a worse reputation, JavaScript or PHP?

There has a been a lot of criticism of PHP over being a badly designed programming language. JavaScript seems quite a similar language with loose-typing and flexible array declarations/memory management, but is widely adopted by industry leaders such as Google. Google even has a JavaScript style guide. Many people think that PHP has a worse reputation than JavaScript. Carlos Ribeiro gave his analysis on a high level which doesn't touch the language syntax. Attributing JavaScript success to it be...

   JavaScript,PHP,reputation,comparison     2014-05-03 06:26:10

  Ways to check existence of JavaScript object

The design of JavaScript is not so sophisticated. It's very easy for us to make mistakes if we are not very careful when using JavaScript. For example, to check the existence of JavaScript object. Now we want to check whether a global object myObj exists or not, if it doesn't exist, we declare it. The pseudo code for this is : if(myObj not exist){ declare myObj; } You may think it's very easy to write the code. In fact, it is much more difficult than we may think. Juriy Zaytsev says there are m...

   JAVASCRIPT,OBJECT,EXISTENCE     2020-09-12 02:14:02

  ECMAScript 6 looks promising

I am quite excited about ECMAScript 6, after watching David Herman’s talk at YUIConf 2011. I am especially looking forward to seeing some of these features landing up on V8 soon, so that I can use it on node.js. These additions will solve many common sources of frustration that newcomers face when working with JavaScript. Although the spec is not expected to be finalized till 2013 (so says David in the video), a lot of these features are expected to hit Chrome and Firefox much befor...

   ECMAScript 6,JavaScript,new feature,let,template     2011-12-07 03:21:40

  JavaScript: Private variables

The first thing you often hear when talking about JavaScript is often “JavaScript doesn’t have visibility modifiers, hence it doesn’t support private variables”. This is only valid for 50%, because JavaScript indeed doesn’t have visibility modifiers (public, private, friend) but it has closures and function scopes. With these tools we can make variables private. Let’s take the following function: var names = ["Kenneth", "John", "Marc", "Robert"]; var lookup =...

   JavaScript,private variable,closure     2012-04-28 11:46:34

  Let's talk about JavaScript deep clone

In JavaScript, deep clone means creating a brand new object that includes all nested objects, with all properties being completely independent copies. This is different from shallow copying, which only copies the first-level properties, with nested objects being referenced rather than copied. There are multiple ways to perform deep copying in JavaScript, but the best one to use depends on the specific use case. Can use JSON.parse & JSON.stringify? ❌ JSON.parse(JSON.stringify(obj)) is a dep...

   JAVASCRIPT,DEEP CLONE     2023-02-25 08:57:11

  Update parent window after closing the window opened by window.open()

Imagine we have a webpage which has a text field to let user enter a date. Usually, we may create a calendar window to ask the user to pick one date from the calendar window, when the date is picked, the calendar window will close and the date picked will be put into the text field. This way involves the window.open() method in JavaScript, and we may think how the opened window knows its parent window and then updates the parent window. I give a simple demo on this.We have two pages, on is the p...

   window.open, JavaScript,update, return value     2012-06-23 01:36:32

  Inspiring facts about JavaScript

JavaScript has been advocated as the first language to be learned by people who want to program. We have discussed the reasons why we should do so. Recently with the popularity of Node.js, JavaScript has become a full-stack language,  it can be used as both frontend and backend programming language. Today we will give some hard facts which will convince you about the popularity of JavaScript. Just like William Ting said ""JavaScript will stay relevant as long as people use the internet". Ye...

   JavaScript,popularity     2014-06-07 08:52:36

  Microsoft Edge extension manifest v2 migration to v3

In June 2023, Microsoft Edge would not allow Edge extensions with manifest version before v3 to be listed on Microsoft web stores as v3 extensions add more security privacy related restrictions on some of the functions. Hence all extensions with manifest v2 must migrate to v3. In this post, we would show how we did the migration for one of our extensions and the changes made. There is a checklist provided by Microsoft Edge team on what needs to be updated so that the extension can stil...

   MICROSOFT EDGE,EXTENSION,MANIFEST V3     2022-10-01 02:54:47

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