var isEmpty = function(s) {				
		var regexpWhitespace = /^\s+$/;
		return  ((s == null) || (s.length == 0) || regexpWhitespace.test(s));
	}
	
	var isAlpha = function(s) {
		var regexpAlphabetic = /^[a-zA-Z\s]+$/; // Add ' and - ?
		return isEmpty(s) || regexpAlphabetic.test(s);
	}
	
	var isAlphaNum = function(s) {
		var validChars = /^[\w\s]+$/;
		return isEmpty(s) || validChars.test(s);
	}
	
	var isDate = function(s) {
		var testDate = new Date(s);
		return isEmpty(s) || !isNaN(testDate);
	}
	
	var isEmail = function(s) {
		var regexpEmail = /\w{1,}[@][\w\-]{1,}([.]([\w\-]{1,})){1,3}$/
		return regexpEmail.test(s);
	}
	
	var isInteger = function(s) {
		var regexp = /^[+]?\d+$/;
		return isEmpty(s) || regexp.test(s);
	}
	
	var isFloat = function(s) {		
		return isEmpty(s) || !isNaN(parseFloat(s));
	}