Javascript object with read only properties

Using the Object.create() method you can specify the writable property in the descriptor, which lets you choose either to make the property writable or not (read-only), here it is:

var myObject = Object.create(Object.prototype, {
    prop: {
        value: 123,
        writable: false
    }
});

Now you can try to re-write your property and you'll see that it stays unchanged:

console.log(myObject.prop); // 123

myObject.prop = 0;
console.log(myObject.prop); // 123

For more information about the Object.create() method see the MDN documentation.