// ===================================================================


// Author: Matt Kruse <matt@mattkruse.com>


// WWW: http://www.mattkruse.com/


//


// NOTICE: You may use this code for any purpose, commercial or


// private, without any further permission from the author. You may


// remove this notice from your final code if you wish, however it is


// appreciated by the author if at least my web site address is kept.


//


// You may *NOT* re-distribute this code in any way except through its


// use. That means, you can include it in your product, or your web


// site, or any other form where the code is actually being used. You


// may not put the plain javascript up on your site for download or


// include it in your javascript libraries for download. 


// If you wish to share this code with others, please just point them


// to the URL instead.


// Please DO NOT link directly to my .js files from your site. Copy


// the files to your server and use them there. Thank you.


// ===================================================================





// HISTORY


// ------------------------------------------------------------------


// May 17, 2003: Fixed bug in parseDate() for dates <1970


// March 11, 2003: Added parseDate() function


// March 11, 2003: Added "NNN" formatting option. Doesn't match up


//                 perfectly with SimpleDateFormat formats, but 


//                 backwards-compatability was required.





// ------------------------------------------------------------------


// These functions use the same 'format' strings as the 


// java.text.SimpleDateFormat class, with minor exceptions.


// The format string consists of the following abbreviations:


// 


// Field        | Full Form          | Short Form


// -------------+--------------------+-----------------------


// Year         | yyyy (4 digits)    | yy (2 digits), y (2 or 4 digits)


// Month        | MMM (name or abbr.)| MM (2 digits), M (1 or 2 digits)


//              | NNN (abbr.)        |


// Day of Month | dd (2 digits)      | d (1 or 2 digits)


// Day of Week  | EE (name)          | E (abbr)


// Hour (1-12)  | hh (2 digits)      | h (1 or 2 digits)


// Hour (0-23)  | HH (2 digits)      | H (1 or 2 digits)


// Hour (0-11)  | KK (2 digits)      | K (1 or 2 digits)


// Hour (1-24)  | kk (2 digits)      | k (1 or 2 digits)


// Minute       | mm (2 digits)      | m (1 or 2 digits)


// Second       | ss (2 digits)      | s (1 or 2 digits)


// AM/PM        | a                  |


//


// NOTE THE DIFFERENCE BETWEEN MM and mm! Month=MM, not mm!


// Examples:


//  "MMM d, y" matches: January 01, 2000


//                      Dec 1, 1900


//                      Nov 20, 00


//  "M/d/yy"   matches: 01/20/00


//                      9/2/00


//  "MMM dd, yyyy hh:mm:ssa" matches: "January 01, 2000 12:30:45AM"


// ------------------------------------------------------------------





var MONTH_NAMES=new Array('January','February','March','April','May','June','July','August','September','October','November','December','Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec');


var DAY_NAMES=new Array('Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday','Sun','Mon','Tue','Wed','Thu','Fri','Sat');


function LZ(x) {return(x<0||x>9?"":"0")+x}





// ------------------------------------------------------------------


// isDate ( date_string, format_string )


// Returns true if date string matches format of format string and


// is a valid date. Else returns false.


// It is recommended that you trim whitespace around the value before


// passing it to this function, as whitespace is NOT ignored!


// ------------------------------------------------------------------


function isDate(val,format) {


	var date=getDateFromFormat(val,format);


	if (date==0) { return false; }


	return true;


	}





// -------------------------------------------------------------------


// compareDates(date1,date1format,date2,date2format)


//   Compare two date strings to see which is greater.


//   Returns:


//   1 if date1 is greater than date2


//   0 if date2 is greater than date1 of if they are the same


//  -1 if either of the dates is in an invalid format


// -------------------------------------------------------------------


function compareDates(date1,dateformat1,date2,dateformat2) {


	var d1=getDateFromFormat(date1,dateformat1);


	var d2=getDateFromFormat(date2,dateformat2);


	if (d1==0 || d2==0) {


		return -1;


		}


	else if (d1 > d2) {


		return 1;


		}


	return 0;


	}





// ------------------------------------------------------------------


// formatDate (date_object, format)


// Returns a date in the output format specified.


// The format string uses the same abbreviations as in getDateFromFormat()


// ------------------------------------------------------------------


function formatDate(date,format) {


	format=format+"";


	var result="";


	var i_format=0;


	var c="";


	var token="";


	var y=date.getYear()+"";


	var M=date.getMonth()+1;


	var d=date.getDate();


	var E=date.getDay();


	var H=date.getHours();


	var m=date.getMinutes();


	var s=date.getSeconds();


	var yyyy,yy,MMM,MM,dd,hh,h,mm,ss,ampm,HH,H,KK,K,kk,k;


	// Convert real date parts into formatted versions


	var value=new Object();


	if (y.length < 4) {y=""+(y-0+1900);}


	value["y"]=""+y;


	value["yyyy"]=y;


	value["yy"]=y.substring(2,4);


	value["M"]=M;


	value["MM"]=LZ(M);


	value["MMM"]=MONTH_NAMES[M-1];


	value["NNN"]=MONTH_NAMES[M+11];


	value["d"]=d;


	value["dd"]=LZ(d);


	value["E"]=DAY_NAMES[E+7];


	value["EE"]=DAY_NAMES[E];


	value["H"]=H;


	value["HH"]=LZ(H);


	if (H==0){value["h"]=12;}


	else if (H>12){value["h"]=H-12;}


	else {value["h"]=H;}


	value["hh"]=LZ(value["h"]);


	if (H>11){value["K"]=H-12;} else {value["K"]=H;}


	value["k"]=H+1;


	value["KK"]=LZ(value["K"]);


	value["kk"]=LZ(value["k"]);


	if (H > 11) { value["a"]="PM"; }


	else { value["a"]="AM"; }


	value["m"]=m;


	value["mm"]=LZ(m);


	value["s"]=s;


	value["ss"]=LZ(s);


	while (i_format < format.length) {


		c=format.charAt(i_format);


		token="";


		while ((format.charAt(i_format)==c) && (i_format < format.length)) {


			token += format.charAt(i_format++);


			}


		if (value[token] != null) { result=result + value[token]; }


		else { result=result + token; }


		}


	return result;


	}


	


// ------------------------------------------------------------------


// Utility functions for parsing in getDateFromFormat()


// ------------------------------------------------------------------


function _isInteger(val) {


	var digits="1234567890";


	for (var i=0; i < val.length; i++) {


		if (digits.indexOf(val.charAt(i))==-1) { return false; }


		}


	return true;


	}


function _getInt(str,i,minlength,maxlength) {


	for (var x=maxlength; x>=minlength; x--) {


		var token=str.substring(i,i+x);


		if (token.length < minlength) { return null; }


		if (_isInteger(token)) { return token; }


		}


	return null;


	}


	


// ------------------------------------------------------------------


// getDateFromFormat( date_string , format_string )


//


// This function takes a date string and a format string. It matches


// If the date string matches the format string, it returns the 


// getTime() of the date. If it does not match, it returns 0.


// ------------------------------------------------------------------


function getDateFromFormat(val,format) {


	val=val+"";


	format=format+"";


	var i_val=0;


	var i_format=0;


	var c="";


	var token="";


	var token2="";


	var x,y;


	var now=new Date();


	var year=now.getYear();


	var month=now.getMonth()+1;


	var date=1;


	var hh=now.getHours();


	var mm=now.getMinutes();


	var ss=now.getSeconds();


	var ampm="";


	


	while (i_format < format.length) {


		// Get next token from format string


		c=format.charAt(i_format);


		token="";


		while ((format.charAt(i_format)==c) && (i_format < format.length)) {


			token += format.charAt(i_format++);


			}


		// Extract contents of value based on format token


		if (token=="yyyy" || token=="yy" || token=="y") {


			if (token=="yyyy") { x=4;y=4; }


			if (token=="yy")   { x=2;y=2; }


			if (token=="y")    { x=2;y=4; }


			year=_getInt(val,i_val,x,y);


			if (year==null) { return 0; }


			i_val += year.length;


			if (year.length==2) {


				if (year > 70) { year=1900+(year-0); }


				else { year=2000+(year-0); }


				}


			}


		else if (token=="MMM"||token=="NNN"){


			month=0;


			for (var i=0; i<MONTH_NAMES.length; i++) {


				var month_name=MONTH_NAMES[i];


				if (val.substring(i_val,i_val+month_name.length).toLowerCase()==month_name.toLowerCase()) {


					if (token=="MMM"||(token=="NNN"&&i>11)) {


						month=i+1;


						if (month>12) { month -= 12; }


						i_val += month_name.length;


						break;


						}


					}


				}


			if ((month < 1)||(month>12)){return 0;}


			}


		else if (token=="EE"||token=="E"){


			for (var i=0; i<DAY_NAMES.length; i++) {


				var day_name=DAY_NAMES[i];


				if (val.substring(i_val,i_val+day_name.length).toLowerCase()==day_name.toLowerCase()) {


					i_val += day_name.length;


					break;


					}


				}


			}


		else if (token=="MM"||token=="M") {


			month=_getInt(val,i_val,token.length,2);


			if(month==null||(month<1)||(month>12)){return 0;}


			i_val+=month.length;}


		else if (token=="dd"||token=="d") {


			date=_getInt(val,i_val,token.length,2);


			if(date==null||(date<1)||(date>31)){return 0;}


			i_val+=date.length;}


		else if (token=="hh"||token=="h") {


			hh=_getInt(val,i_val,token.length,2);


			if(hh==null||(hh<1)||(hh>12)){return 0;}


			i_val+=hh.length;}


		else if (token=="HH"||token=="H") {


			hh=_getInt(val,i_val,token.length,2);


			if(hh==null||(hh<0)||(hh>23)){return 0;}


			i_val+=hh.length;}


		else if (token=="KK"||token=="K") {


			hh=_getInt(val,i_val,token.length,2);


			if(hh==null||(hh<0)||(hh>11)){return 0;}


			i_val+=hh.length;}


		else if (token=="kk"||token=="k") {


			hh=_getInt(val,i_val,token.length,2);


			if(hh==null||(hh<1)||(hh>24)){return 0;}


			i_val+=hh.length;hh--;}


		else if (token=="mm"||token=="m") {


			mm=_getInt(val,i_val,token.length,2);


			if(mm==null||(mm<0)||(mm>59)){return 0;}


			i_val+=mm.length;}


		else if (token=="ss"||token=="s") {


			ss=_getInt(val,i_val,token.length,2);


			if(ss==null||(ss<0)||(ss>59)){return 0;}


			i_val+=ss.length;}


		else if (token=="a") {


			if (val.substring(i_val,i_val+2).toLowerCase()=="am") {ampm="AM";}


			else if (val.substring(i_val,i_val+2).toLowerCase()=="pm") {ampm="PM";}


			else {return 0;}


			i_val+=2;}


		else {


			if (val.substring(i_val,i_val+token.length)!=token) {return 0;}


			else {i_val+=token.length;}


			}


		}


	// If there are any trailing characters left in the value, it doesn't match


	if (i_val != val.length) { return 0; }


	// Is date valid for month?


	if (month==2) {


		// Check for leap year


		if ( ( (year%4==0)&&(year%100 != 0) ) || (year%400==0) ) { // leap year


			if (date > 29){ return 0; }


			}


		else { if (date > 28) { return 0; } }


		}


	if ((month==4)||(month==6)||(month==9)||(month==11)) {


		if (date > 30) { return 0; }


		}


	// Correct hours value


	if (hh<12 && ampm=="PM") { hh=hh-0+12; }


	else if (hh>11 && ampm=="AM") { hh-=12; }


	var newdate=new Date(year,month-1,date,hh,mm,ss);


	return newdate.getTime();


	}





// ------------------------------------------------------------------


// parseDate( date_string [, prefer_euro_format] )


//


// This function takes a date string and tries to match it to a


// number of possible date formats to get the value. It will try to


// match against the following international formats, in this order:


// y-M-d   MMM d, y   MMM d,y   y-MMM-d   d-MMM-y  MMM d


// M/d/y   M-d-y      M.d.y     MMM-d     M/d      M-d


// d/M/y   d-M-y      d.M.y     d-MMM     d/M      d-M


// A second argument may be passed to instruct the method to search


// for formats like d/M/y (european format) before M/d/y (American).


// Returns a Date object or null if no patterns match.


// ------------------------------------------------------------------


function parseDate(val) {


	var preferEuro=(arguments.length==2)?arguments[1]:false;


	generalFormats=new Array('y-M-d','MMM d, y','MMM d,y','y-MMM-d','d-MMM-y','MMM d');


	monthFirst=new Array('M/d/y','M-d-y','M.d.y','MMM-d','M/d','M-d');


	dateFirst =new Array('d/M/y','d-M-y','d.M.y','d-MMM','d/M','d-M');


	var checkList=new Array('generalFormats',preferEuro?'dateFirst':'monthFirst',preferEuro?'monthFirst':'dateFirst');


	var d=null;


	for (var i=0; i<checkList.length; i++) {


		var l=window[checkList[i]];


		for (var j=0; j<l.length; j++) {


			d=getDateFromFormat(val,l[j]);


			if (d!=0) { return new Date(d); }


			}


		}


	return null;


	}