// ===================================================================
// 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.
// ===================================================================


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

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');
// wenn das eingegebene Datum falsch war, wird auch false gesetzt
var aIsDateValue = true;

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,objInput) {
	
	format=format+"";
	var result="";
	var i_format=0;
	var c="";
	var token="";
	var y=date.getFullYear()+"";
	var M=date.getMonth()+1;
	var d=date.getDate();
	var yyyy,yy,MMM,MM,dd;
	
	// 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["d"]=d;
	value["dd"]=LZ(d);
	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; 
		}
	}
	
	if (aIsDateValue == false){
		objInput.focus();
		objInput.select();
	}
	
	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,ErrorStr,ErrorStrActual) {
	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.getFullYear();
	var month=now.getMonth()+1;
	var date=now.getDate();
	var hh=now.getHours();
	var mm=now.getMinutes();
	var ss=now.getSeconds();
	var ampm="";
	var dtToday = new Date();
    dtToday = dateToString(dtToday);
    DateString = dtToday.split(".");
    
	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; }
			yearhelp=_getInt(val,i_val,x,y);
			if (yearhelp==null) { 
				alert(ErrorStr);
				aIsDateValue = false;
				var newdate = new Date(DateString[2],DateString[1]-1,DateString[0]);
				return newdate.getTime();
				return false;
				}
			else{
				year = yearhelp;
				if ((year.length == 4) && ((year < 1753) || (year > 9000))){
					alert(ErrorStrActual);
					aIsDateValue = false;
					var newdate = new Date(DateString[2],DateString[1]-1,DateString[0]);
					return newdate.getTime();
				}
			  
			}
			i_val += year.length;
			}
		
		else if (token=="MMM"){
			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()) {
					month=i+1;
					if (month>12) { month -= 12; }
					i_val += month_name.length;
					break;
					}
				}
			if ((month < 1)||(month>12)){return 0;}
			}
			
		else if (token=="MM"||token=="M") {
			monthhelp=_getInt(val,i_val,token.length,2);
			if(monthhelp==null||(monthhelp<1)||(monthhelp>12)){
				alert(ErrorStr);
				aIsDateValue = false;
				var newdate = new Date(DateString[2],DateString[1]-1,DateString[0]);
				return newdate.getTime();
				return false;
			}
			else {
				month = monthhelp;
			}
			
			i_val+=month.length;}
		
		else if (token=="dd"||token=="d") {
			datehelp=_getInt(val,i_val,token.length,2);
			if(datehelp==null||(datehelp<1)||(datehelp>31)){
				alert(ErrorStr);
				aIsDateValue = false;
				var newdate = new Date(DateString[2],DateString[1]-1,DateString[0]);
				return newdate.getTime();
				return false;
			}
			else{
				date = datehelp;
			 }
			i_val+=date.length;
		}
		
		else {
			if (val.substring(i_val,i_val+token.length)!=token) {
				alert(ErrorStr);
				aIsDateValue = false;
				var newdate = new Date(DateString[2],DateString[1]-1,DateString[0]);
				return newdate.getTime();
				return false;
			}
			else {
				i_val+=token.length;}
			}
		}
	// If there are any trailing characters left in the value, it doesn't match
	if (i_val != val.length) {
		alert(ErrorStr);
		aIsDateValue = false;
		var newdate = new Date(DateString[2],DateString[1]-1,DateString[0]);
		return newdate.getTime();
		return false;
	  }
	// 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){ 
				alert(ErrorStr);
				aIsDateValue = false;
				var newdate = new Date(DateString[2],DateString[1]-1,DateString[0]);
				return newdate.getTime();
				return false;
			}
		}
		else { 
			if (date > 28) { 
				alert(ErrorStr);
				aIsDateValue = false;
				var newdate = new Date(DateString[2],DateString[1]-1,DateString[0]);
				return newdate.getTime();
				return false;
			} 
		}
	}
	if ((month==4)||(month==6)||(month==9)||(month==11)) {
		if (date > 30) {
			alert(ErrorStr);
			aIsDateValue = false;
			var newdate = new Date(DateString[2],DateString[1]-1,DateString[0]);
			return newdate.getTime();
			return false;
		  }
		}
	
	var newdate = new Date(year,month-1,date);
	return newdate.getTime();
	}