- Javascript is a most popular interpreted compiled as well as case sensitive programming language.
- It can be used for both client-side as well as server-side developments.
- It is simply a synchronous single-threaded language.
- Single-threaded means that javascript can only execute one command at a time.
- And Synchronous single-threaded means that javascript can only execute one command at a time and in a specific order.
- So that means it can only go to the next line once the current line has been finished executing.
- Evolution of javascript: Created in 1995 by brendan Eich while he was working on Netscape and became an ECMA standard in 1997.
- ECMA-262 is the official name of the standard. ECMAScript is the official name of the language.
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"Everything in Javascript happens inside an EXECUTION CONTEXT". The execution context is like a big box or container where the JavaScript code is executed.
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When a Javascript code is executed, an Execution Context is created and it is called as Global Execution Context.
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A javascript program is executed in 2 phases inside the Execution Context.
- MEMORY ALLOCATION PHASE :
- The browser initially scans the JS code and allocates memory for variables and functions defined in the program.
- The memory component is also known as the variable environment.
- So it is a sort of environment in which all these variables and functions are stored as key-value pairs.
- CODE EXECUTION PHASE :
- This is the place where code is executed one line by line at a time. It is also known as the thread of execution.
- Javascript is interpreted line by line and the code is executed.
- MEMORY ALLOCATION PHASE :
