JavaScript Variables - School4Tech

JavaScript Variables have three types of scope:

Global – a global variable can be accessed from anywhere in the code. by default it is global if nothing specify.
Local- a local variable will be visible only within a function.
Const – declare a constant. Once assigned value, it cannot be reassign. if tried to reassign, it will give TypeError: Assignment to constant variable

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <p id="mydiv1"></p>
  <p id="mydiv2"></p>
  <p id="mydiv3"></p>
  <script type="text/javascript">
    function checkscope() {
      var globe = "global  "; // Declare a global variable
      let local = "method local "; // Declare a local variable
      const myConst = "Constant ";   // declare const variable
      document.getElementById("mydiv1").innerHTML = 'Local Variable: ' + local;
      document.getElementById("mydiv2").innerHTML = 'Global Variable: ' + globe;
      document.getElementById("mydiv3").innerHTML = 'Const Variable: ' + myConst;
    }
    checkscope();
  </script>
</body>
</html>

<!DOCTYPE html>

<head>

<title>Document</title>

</head>

<body>

function checkscope() {

var globe = "global "; // Declare a global variable

let local = "method local "; // Declare a local variable

const myConst = "Constant "; // declare const variable

document.getElementById("mydiv1").innerHTML = 'Local Variable: ' + local;

document.getElementById("mydiv2").innerHTML = 'Global Variable: ' + globe;

document.getElementById("mydiv3").innerHTML = 'Const Variable: ' + myConst;

}

checkscope();

</script>

</body>

</html>

JavaScript Reserved Words

Below table list of all the reserved words in JavaScript are given in the following table.
These cannot be used as JavaScript variables, functions or any object names.

abstract	else	instanceof	switch
boolean	enum	int	synchronized
break	export	interface	this
byte	extends	long	throw
case	false	native	throws
catch	final	new	transient
char	finally	null	true
class	float	package	try
const	for	private	typeof
continue	function	protected	var
debugger	goto	public	void
default	if	return	volatile
delete	implements	short	while
do	import	static	with
double	in	super

JavaScript Reserved Words

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