Declaring global variables in JavaScript

This explains different ways of declaring global variables and necessary precautions need to be taken while doing so.

To begin with, in JavaScript to declare a variable we use var

Ex: var myVar;

If the variable declared inside a function or control structure its scope is limited to that particular function/control block only.

To declare global variables in JavaScript, just declare them outside functions.
But, is there a way to declare global variable inside the function? The answer is yes, we can.
One could declare global variable by removing var keyword and use that directly

Ex: myVar = ‘str’;

If you assign a value in this manner, myVar becomes a global variable.

Note: Please be careful while doing this as if you have any other variables with the same name in global scope (within the same js file or even external files which might be having global variables), it could cause adverse results.