JSFiddle - React, Tailwind, and code Playground

HTML

<button type="button">click</button>

JavaScript

var checkObject = function() {};

checkObject.prototype.checkName = function(){

};

checkObject.prototype.checkEmail = function() {

}

checkObject.prototype.checkPassword = function(){
	alert(this.checkObject)
  alert(this.checkEmail)
}


var a = new checkObject();
a.checkPassword();