//object with a private setter in JavaScript
//lulz.A can only be set via a special function and the value needs to be a number
function lulz(){
	var a=0;
	Object.defineProperty(this, 'A',{
		get:function(){return +a;},
		enumerable:true,
		configurable:false
	});
	this.setA=function(q){
		//only allow numbers
		if(+q==+q){return a=+q;}
	};
	return this;
}

var test=new lulz();
//Check initial
console.log("A must be 0 as initial value:",test.A===0);
//Try direct modify
test.A=12;
console.log("A must be 0 after assigning 12 directly:",test.A===0);
//Try direct modify
test.A="Q";
console.log("A must be 0 after assigning 'Q' directly:",test.A===0);
//Try indirect modify with string
test.setA("Q");
console.log("A must be 0 after assigning 'Q' via set function:",test.A===0);
//Try indirect modify with number
test.setA(12);
console.log("A must be 12 after assigning 12 via set function:",test.A===12);