// Sorting table columns correctly by text, number or date. There are other 
// versions, plugins, etc., for this but they either are restricted to specific 
// date formats, or require EVERY row-element to be given a sort attribute; mine 
// can handle many different date and number formats, and even allows for specific 
// cells that may not conform to the overall date/number format for that column. 
// My version also enables sorting of element hierarchies: such as a DIV containing 
// P-paragraphs and SPANs - this could even be an image-gallery containing prices 
// or dates within spans. Very efficient as well!!
// Example: andrew.dx.am/sortgallerydel.html
// AddSortToTables(); will make the table headers clickable, to sort columns in 
// ascending or descending order, for any tables with class="sortIt".
// SortTable(tbl, col); will sort the table (tbl is an id or table object) by 
// the supplied column index (indexed from 0) in ascending or descending order.
// AddSortByDate(tbl, col, dateMask); enables sorting of a column by date, 
// specified by a date-mask such as 'dd-mmm-yy'.
// AddSortByNumber(tbl, col); enables sorting of a column by number. This assumes a 
// period . as the decimal separator (if present); it ignores any other non-numeric 
// characters.
// SortElements(parentEl, childTag, colTag, colIndex); will sort (non-table) 
// elements in ascending or descending order. For example, an UL containing LIs 
// and SPANs. colIndex specifies which span to sort; there may be more than one in 
// the LI (0 indexed).
// Example: SortElements('divid', 'p', 'span', 2);
// 3rd span within each paragraph.
//
// AddSortByDate2(parentEl, childTag, colTag, colIndex, dateMask); and 
// AddSortByNumber2(parentEl, childTag, colTag, colIndex)
// provide the same feature-set as AddSortByDate and AddSortByNumber does 
// for tables, but for element hierarchies.
// If there are dates or numbers in a column (or element) which don't meet the 
// date-mask or number formatting necessary to sort correctly, then these individual 
// elements can be given the attribute "sort" and they will still sort correctly!
// For example, with a date column <td sort="2012/12/20"> will still sort a 
// cell correctly. (This format 'YYYY/MM/DD' will be converted into a Date() object.)
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 AddEvent = function (elem, eventType, func) {
  // Helper function.
  if ( elem.addEventListener )
    AddEvent = function (elem, eventType, func) {
      elem.addEventListener(eventType, func, false);
    };
  else if ( elem.attachEvent )
    AddEvent = function (elem, eventType, func) {
      elem.attachEvent('on' + eventType, func);
    };
  else
    AddEvent = function (elem, eventType, func) {
      elem['on' + eventType] = func;
    };
  AddEvent(elem, eventType, func);
};
// Sort methods/algorithms attributed:
var SortTable = function (tbl, col) {
  // could be called directly
  SortElements(tbl, 'tr', 'td', col);
};
var SortElements = function (parentEl, childTag, colTag, colIndex) {
  // example use: SortElements('table1','tr','td',2)
  // or SortElements('list1','li')
  // or SortElements('divName','p','span',3)
  var i, j, cTags = {}, startAt = 0, childLen, aChild, elem,
    sortBy, content, elems = [], sortedLen, frag, hdrsLen, hdr;
  var parent = (typeof parentEl === 'string') "Click to sort"
          if ( !hdrs[j].title ) hdrs[j].setAttribute('title',
            'Click to sort');
        }
      }
    }
  }
};
var AddSortByDate = function (tbl, col, dateMask) {
  // Input: the table name (or object), a column index (or array) 
  // and a date mask ('dd-mmm-yy')
  // Adds a sortBy = 'date' property to the first row
  // will ignore the first row, assuming it is a header row
  var i, rLen, cell;
  while ( col.length ) AddSortByDate(tbl,col.pop(),dateMask);
  if ((col instanceof Array) || isNaN(col)) return;
  var tbl = (typeof tbl === 'string') "NaN" || cell.dateValue.toString() == 
          "Invalid Date") {
        cell.dateValue = 0;
      } 
    }
  }
};
var AddSortByNumber = function (tbl, col) {
  // col is a column index or array of indices
  // will ignore the first row, assuming it is a header row
  var i, rLen, cell, tempNum;
  while ( col.length ) AddSortByNumber(tbl,col.pop());
  if ((col instanceof Array) || isNaN(col)) return;
  tbl = (typeof tbl === 'string') "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]|$)/)+1;
  if ( fndSingle ) return ''; // do not attempt to parse, for example, 'DMM'
  sFormat = sFormat.replace(/(^|[^Y])(YY)(?=[^Y]|$)/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 : '';
};