/*
    jqueryui的datepicker的string转日期
    [-][+]20[y][m][w][d] 表示偏移多少
    利用了new Date()传入不合法参数也能转换的特性 = .=
   /  this.getOffsetDate = function(offset){
    var date = new Date(),
      year = date.getFullYear(),
      month = date.getMonth(),
      day = date.getDate(),      pattern = /([+-]?[0-9]+)\s(d|D|w|W|m|M|y|Y)?/g,
      matches = pattern.exec(offset);
while (matches) {
  switch (matches[2] || “d”) {        case “d” : case “D” :
    day += parseInt(matches[1],10); break;
    case “w” : case “W” :
    day += parseInt(matches[1],10) * 7; break;
    case “m” : case “M” :        month += parseInt(matches[1],10);
    break;
    case “y”: case “Y” :
    year += parseInt(matches[1],10);
    break;      }
  matches = pattern.exec(offset);
}
return new Date(year, month, day);
}