Javascript Date Parser

(function() {
    var parseDate = function(date) {
        date = date.replace(/\-/g, '/');
        date = date.replace(/(\d{1,2})[\/\-](\d{1,2})[\/\-](\d{2})/, '$1/$2/$3');
        return new Date(date).getTime() || -1;
    };
    Tablesort.extend('date', function(item) {
        return (item.search(/(Mon|Tue|Wed|Thu|Fri|Sat|Sun)\.?\,?\s*/i) !== -1 || item.search(/\d{1,2}[\/\-]\d{1,2}[\/\-]\d{2,4}/) !== -1 || item.search(/(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)/i) !== -1) && !isNaN(parseDate(item));
    }, function(a, b) {
        a = a.toLowerCase();
        b = b.toLowerCase();
        return parseDate(b) - parseDate(a);
    });
}());