error - require is not defined . How to write a json file with the help of javascript

Question

I want to make a level editor for my platformer game with phaser and I am saving the data in json files. I want to write json with javascript and I searched then i came to know that we can write it first writing this const fs = require("fs") and many more but on this line I get error require is not defined. I want to create a json file. I using it in the browser with windows 7. how can I use require to do so.

If there is any other way to write json file with js, then please tell.