jQuery.validator.addMethod("alphanumeric", function(value, element) {
	return this.optional(element) || /^\w+$/i.test(value);
}, "Letters, numbers, spaces or underscores only please"); 

jQuery.validator.addMethod("nowhitespace", function(value, element) {
	return this.optional(element) || /^\S+$/i.test(value);
}, "No white space please"); 

/**
  * Return true, if the value is a valid date, also making this formal check mm/dd/yyyy.
  *
  * @example jQuery.validator.methods.date("01/01/1900")
  * @result true
  *
  * @example jQuery.validator.methods.date("13/40/1900")
  * @result false
  *
  * @name jQuery.validator.methods.dateITA
  * @type Boolean
  * @cat Plugins/Validate/Methods
  */
jQuery.validator.addMethod(
	"real_date",
	function(value, element) {
		var check = false;
		var re = /^\d{1,2}\/\d{1,2}\/\d{4}$/
		if( re.test(value)){
			var adata = value.split('/');
			var mm = parseInt(adata[0],10);
			var gg = parseInt(adata[1],10);
			var aaaa = parseInt(adata[2],10);
			var xdata = new Date(aaaa,mm-1,gg);
			if ( ( xdata.getFullYear() == aaaa ) && ( xdata.getMonth () == mm - 1 ) && ( xdata.getDate() == gg ) )
				check = true;
			else
				check = false;
		} else
			check = false;
		return this.optional(element) || check;
	}, 
	"Please enter a correct date"
);