Javascript-Variables
A JavaScript variable is simply known as the storage location. There are two types of variables in local variable and global variable.
There are some rules while declaring a JavaScript variable (known as identifiers).
- The name must start with a letter (a to z or A to Z), underscore( _ ), or dollar( $ ) sign.
- After the first letter, we can use the digits 0 to 9.
- JavaScript variables are case sensitive( x and X are different variables).
Example :
<html> <body> <script> var x = 10; var y = 70; var z=x+y; document.write(z); </script> </body> </html>
OUTPUT:
80
local variable :
It is declared inside block or function. It is accessible within the function or block only.
<script> function abc(){ var x=10;//local variable } </script>
OR
<script> If(10<13){ var y=20;//JavaScript local variable } </script>
global variable:
It is accessible from any function. A variable i.e. declared outside the function or declared with a window object is known as a global variable.
Example:
<html> <body> <script> var data=500;//gloabal variable function a(){ document.writeln(data); } function b(){ document.writeln(data); } a();//calling JavaScript function b(); </script> </body> </html>
OUTPUT:
500 500