Returns the date in the yyyy-mm-dd format.
@param {Date} The date object to operate on.
@param {String} [delim='-'] The delimiter to used the separate the date components (e.g. '-' or '.')
@returns {String} The date in the yyyy-mm-dd format.
@function
function yyyymmdd (d, delim) {
                    if(!(d instanceof Date)) return d;
                    delim = typeof delim !== 'string' ? '-' : delim ;

                    var dd   = d.getDate(),
                        mm   = d.getMonth() + 1,
                        yyyy = d.getFullYear();

                    if(dd < 10) dd = '0' + dd;
                    if(mm < 10) mm = '0' + mm;
                    return yyyy + delim + mm + delim + dd;
                }