simplest onclick popunder possible

popunder.js

class Popunder {
    constructor(url) {
        this.targetUrl = url || "http://google.com";
        this.cookieName = "popunder";
        this.clicksRequired = 1;
        this.expirationHours = 24;
        this.cookiePath = ";path=/";
        this.eventName = "click";
        this.documentRoot = document.documentElement;
        this.init();
    }

    openPopunder() {
        if (!document.cookie.match(new RegExp(`(^|\\W)${this.cookieName}=1(\\W|$)`))) {
            window.open(this.targetUrl, this.cookieName, "width=1024,height=768,resizable=1,toolbar=1,location=1,menubar=1,status=1,scrollbars=1");
            window.focus();
            let expiresDate = new Date();
            expiresDate.setTime(expiresDate.getTime() + 3600 * this.expirationHours * 1000); // Convert hours to milliseconds
            document.cookie = `${this.cookieName}=1; expires=${expiresDate.toGMTString()}${this.cookiePath}`;
        }
    }

    eventHandler = () => {
        if (--this.clicksRequired === 0) {
            this.openPopunder();
        }
    }

    init() {
        if (typeof this.documentRoot.addEventListener !== "undefined") {
            this.documentRoot.addEventListener(this.eventName, this.eventHandler, false);
        } else if (typeof this.documentRoot.attachEvent !== "undefined") {
            this.documentRoot.attachEvent("on" + this.eventName, this.eventHandler);
        }
    }
}

// Usage example
const myPopunder = new Popunder("http://example.com");