Technical Blog for "Application Frameworks"

The keyword "this" is frequently misunderstood when coding with Javascript. It is because its behavior depends on the execution context. Now what is "execution context"? It is mainly of three types. Global Execution Cotnext (GEC), Functional Execution Cotnext (FEC) and Eval. In GEC, it is the global environment which Javascript  (JS) is running. If you are running the script in a browser and you use the "this" keyword, it will refer to the "Window" object. But if you are using NodeJS and running the script outside a browser the "this" keyword would refer to the "Process". In FEC the "this" keyword would refer to the execution context created by the code inside the function. EVAL is hen you use the "this" keyword inside an "eval" function. If this does not make sense, don't worry because we are going to understand with an example which is always the best way. Make the following HT

Let's understand variable types "var", "let" and "const" in Javascript.  Basically there are 3 ways to create variables in java script using 3 keywords as follows.  There differences are as follows,  01. The "variable01" which was created with "var" keyword, does not have a blocked scope. which means, you have to be careful when using it. A variable declared inside an "if" block can be changed outside the block.  02. The "variable02" which was created with "let" keyword, has blocked scope. A variable with "let" keyword declared inside an "if" block is not available outside the block. 03. The "variable03" which was created with "const" keyword, is a constant. Which means you have to initialize it once you declare it, and that value cannot be modified later in the programs. There will be an error if you try to do so.  Now lets explore