JSFiddle - React, Tailwind, and code Playground

HTML

<input id="name"><button onclick="checkCookie()">Check</button>

JavaScript

function setCookie(name,value,days) {
    var date = new Date();
    date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
    var expires = "; expires=" + date.toGMTString();            
    document.cookie = name + "=" + value + expires + ";";
    alert("Hello you are : "+getCookie(name)); // displaying alert message 'Hello you are :'
}

function getCookie(cname) { //any problem with this code?
    var rcookies = document.cookie;
    var cookiearray = rcookies.split(";");
    for (i=0;i<cookiearray.length;i++){
        var value=cookiearray[i];
        value=value.split("=");
        if(value[0]==cname){
            return value[1];
        }
    }
    return "";
}

function checkCookie() {
    var user = getCookie("user");
    if (user != "") {
        alert("You are " + user); // This alert is Never displayed But it need to be. 
    } else {
        user = document.getElementById("name").value;
        alert(user); // displaying the value of text field
        setCookie("user", user, 1);
    }
}