Exercício sobre expressões regulares

gistfile1.js

	String.prototype.convertDateFormat = function() {
		var pattern = /^(\d{1,2})\/(\d{1,2})\/(\d{4})/;
		var str = "";
		for (var i = 0; i < this.length; i++){
			str += this[i];
		}
		return str.match(pattern)[3] + '-' + str.match(pattern)[2] + '-' + str.match(pattern)[1];
	};
	
	var a = "30/10/2000";
	console.log(a.convertDateFormat());