Untitled

<!DOCTYPE html>
<html>
<head>
<title>Ext-JS Private Problem</title>
<script src="https://cdnjs.cloudflare.com/ajax/libs/extjs/6.0.0/ext-all.js"></script>
<script>
Ext.define('Student', function(){
    var name = 'unnamed';

    return {
        constructor : function(name){
            this.name = name;
        },
        getName : function(){
            alert('Student name is ' + this.name);
        }
    };
});

//create an object of Student class
var studentObj = Ext.create('Student','XYZ');
studentObj.getName();
alert(studentObj.name);
</script>
</head>
<body>
</body>
</html>

<!DOCTYPE html>
<html>
<head>
<title>Ext-JS Private Problem</title>
<script src="https://cdnjs.cloudflare.com/ajax/libs/extjs/6.0.0/ext-all.js"></script>
<script>
Ext.define('Student', function(){
    var name = 'unnamed';

    return {
        constructor : function(n){
            name = n;
        },
        getName : function(){
            alert('Student name is ' + name);
        }
    };
});

//create an object of Student class
var studentObjX = Ext.create('Student','XYZ');
var studentObjA = Ext.create('Student','ABC');
studentObjX.getName();
studentObjA.getName();
</script>
</head>
<body>
</body>
</html>