Object.extend(String.prototype, {
		
	isNumeric: function() {
		//blank strings are always considered valid
		return this == "" || /^-?([0-9]+(\.[0-9]+){0,1}|\.[0-9]+)$/.test(this);
	},
	
	isEmail: function() {
		//blank strings are always considered valid
		return this == "" || /^([a-zA-Z0-9_\.\-])+\@([a-zA-Z0-9.\-])+(\.[a-zA-Z0-9]{2,4})+$/.test(this);
	},
	
	isPhone: function() {
		return this == "" || /(^\d{10}$)|(^(\(\d{3}\) ?|\d{3}[ \-]?)\d{3}[ \-]?\d{4}$)/.test(this);
	}
	
	
  });