Saturday, May 30, 2009

JavaScript Date Functilons


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


// Author: Vipin K R


// WWW:
http://www.careeritdevelopers.blogspot.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) &amp;&amp; (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) &amp;&amp; (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"&amp;&amp;i>11))
{


month=i+1;



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


i_val +=
month_name.length;


break;


}


}


}



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


else if (hh>11 &amp;&amp;
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;


}

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