how to create cookie with users data in htm code example

Example: set and get cookie in javascript

For storing array inside cookie : 
-----------------------------------
setter : var json_str = JSON.stringify(arr); cookie.set('mycookie', json_str);
getter : cookie.get('mycookie'); var arr = JSON.parse(json_str);
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Function common for all type of variable : 
==========================================
let cookie = {
            set: function(name, value) {
                document.cookie = name+"="+value;
            },
            get: function(name) {
                let nameEQ = name + "=";
                let ca = document.cookie.split(';');
                for( let i = 0; i < ca.length; i++ ) {
                    let c = ca[i];
                    while (c.charAt(0)==' ') c = c.substring(1,c.length);
                    if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
                }
                return null;
            }
        }