JavaScript通过Date-Mask将日期转换成字符串的方法

var MonthNames = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"];var DayNames = [ "Sunday", "Monday", "Tueday", "Wednesday", "Thursday",   "Friday", "Saturday" ];var ShortMths = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug",   "Sep", "Oct", "Nov", "Dec"];var ShortDays = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];var StringToDate = function (sDate, sFormat, cutOff) {  // Input: a date value as a string, it's format as a string e.g. 'dd-mmm-yy'  // Optional: a cutoff (integer) for 2 digit years.  // If no 'd' appears in the format string then the 1st of the month is assumed.  // If the year is 20 and the cut-off is 30 then the value will be converted   // to 2020; if the year is 40 then this will be converted to 1940.  // If no cut-off is supplied then '20' will be pre-pended to the year (YY).  // Output: a string in the format 'YYYY/MM/DD' or ''  // Will not attempt to convert certain combinations e.g. DMM, MDD, DDM, YYYYD.  var sParsed, fndSingle;  // sParsed will be constructed in the format 'YYYY/MM/DD'  sDate = sDate.toString().toUpperCase();  sFormat = sFormat.toUpperCase();  if (sFormat.search(/MMMM|MMM/) + 1) { // replace Mar/March with 03, etc.    sDate = sDate.replace(new RegExp('(' + ShortMths.join('|') + ')[A-Z]*', 'gi'),      function (m) {      var i = ShortMths.indexOf(m.charAt(0).toUpperCase() +         m.substr(1, 2).toLowerCase()) + 1;      return ((i < 10) ? "0" + i : "" + i).toString();    });    sFormat = sFormat.replace(/MMMM|MMM/g, 'MM');  }  if (sFormat.search(/DDDD|DDD/) + 1) { // replace Tue/Tuesday, etc. with ''    sDate = sDate.replace(new RegExp('(' + ShortDays.join('|') + ')[A-Z]*', 'gi'),'');    sFormat = sFormat.replace(/DDDD|DDD/g, '');  }  sDate = sDate.replace(/(^|/D)(/d)(?=/D|$)/g, function($0, $1, $2) {    // single digits 2 with 02    return $1 + '0' + $2;  });  sFormat = sFormat.replace(/(^|[^DMY])(D|M)(?=[^DMY]|$)/g, function($0, $1, $2){    return $1 + $2 + $2; // replace D or M with DD and MM  });  // are there still single Ds or Ms?  fndSingle = sFormat.search(/(^|[^D])D([^D]|$)|(^|[^M])M([^M]|$)/)+1;  // do not attempt to parse, for example, 'DMM'  if ( fndSingle ) return '';  sFormat = sFormat.replace(/(^|[^Y])(YY)(?=[^Y]|$)/g, function($0, $1, $2, index) {    var tempDate = sDate.substr(0, index + 1);    tempDate += (cutOff) ? ((parseInt(sDate.substr(index + 1, 2),10) > cutOff) ? '19' : '20') : '20';    tempDate += sDate.substr(index + 1);    sDate = tempDate;    return $1 + $2 + $2;  });  sParsed = ('YYYY/MM/DD').replace(/YYYY|MM|DD/g, function(m){    return (sFormat.indexOf(m) + 1) ?       sDate.substr(sFormat.indexOf(m), m.length) : '';  });  if (sParsed.charAt(0) == '/') {    // if no year specified, assume the current year    sParsed = (new Date().getFullYear()) + sParsed;  }  if (sParsed.charAt(sParsed.length - 1) == '/') {    // if no date, assume the 1st of the month    sParsed += '01';  }  // should end up with 10 characters..  return ( sParsed.length == 10 ) ? sParsed : '';};