Accessing .js file in .html file

How to include custom js file in my custom html file.?
Can anyone suggest me??
The default way (in html) as including it via script tag is not working.

@Kiranmai you can use

<script src="your js file path">

is not working @Jeel

Why not

See these photos.

  1. Function
    image

  2. Script

  3. Usage

  4. Error
    image

Anyone…??

@Kiranmai Can you give us clear picture like where you are writing the script/code and also if possible include some screenshots.