Hijri To Greg http://www.islamicity.org/PrayerTimes/assets/js/prayertime.lib.js?ver=MHK-JUNE-12-2017-0.9

GregToHijri.js

function GregToHijri(arg) {

	console.log ( 'arg' );
	console.log (arg);

	if(arg == ""){
		return "";
	}
	//declare a date format year,month,day sequence
	var arabic_date = new Array(0,0,0);
	var jd;
	var jd1;
	var l;
	var j;
	var n;
	var d = parseInt(arg.getDate());

	var m = parseInt(arg.getMonth()+1); // date type start with 0 - 11, so we need adjust by +1
	var y = parseInt(arg.getFullYear());

	var deltaAdjusted;
	deltaAdjusted = adjustDelta(m,y);


	if ((y>1582)||((y==1582)&&(m>10))||((y==1582)&&(m==10)&&(d>14)))
	{
		//added +delta on jd to comply isna rulling
		jd = intPart((1461*(y+4800+intPart((m-14)/12)))/4)+intPart((367*(m-2-12*(intPart((m-14)/12))))/12)-
				intPart( (3* (intPart(  (y+4900+    intPart( (m-14)/12)     )/100)    )   ) /4)+d-32075 + deltaAdjusted;
	}
	else
	{
		//added +delta on jd to comply isna rulling
		jd = 367*y - intPart((7*(y+5001+intPart((m-9)/7)))/4) + intPart((275*m)/9)+d+1729777 + deltaAdjusted;
	}
	//arg.JD.value=jd
	//added -delta on jd1 to comply isna rulling
	jd1 = jd - deltaAdjusted;
	//arg.wd.value=weekDay(jd1%7)
	l = jd - 1948440 + 10632;
	n = intPart((l-1)/10631);
	l = l-10631*n + 354;
	j = (intPart((10985-l)/5316))*(intPart((50*l)/17719))+(intPart(l/5670))*(intPart((43*l)/15238));
	l = l-(intPart((30-j)/15))*(intPart((17719*j)/50))-(intPart(j/16))*(intPart((15238*j)/43))+29;
	m = intPart((24*l)/709);
	d = l-intPart((709*m)/24);
	y= 30 * n + j - 30;

	arabic_date[2] = d;
	arabic_date[1] = m;
	arabic_date[0] = y;

	return arabic_date;
}

helper.js

function adjustDelta(m,y){
	// whenever there is an adjustment to be made 
	// ( be it for the current month or for a future month/date ), use this! 
	// add new cases, without deleting the previous ones
	// make sure each case comes with its hijriToGreg and GregToHijri pairs ( ex: 1438 & 2017 )
	
	// note whenever you make changes to the scripts, update the version at /prayertimes/version-integer.php
	var bingo = false; // this gets set to true only if there is an adjustment match and allow us to short-circuit the function	
	var returnVal = delta; // this is what comes from the config.js, if no adjustment match occurs, this prevails at the end of the function return
	
	// ramadan 1438 fix
	//-----------------------------------------------------------------
	if ( ( m == 6 && y == 2017 ) ||  ( m == 9 && y == 1438 ) ) {
		bingo = true;
		returnVal = 0; 
	};
	if ( bingo ) {
		return returnVal;
	} 
	//-----------------------------------------------------------------
		
	return returnVal;
}

/** Date conversion English to Arabic and Arabic to English months **/
function intPart(floatNum){
	if (floatNum< -0.0000001){
		 return Math.ceil(floatNum-0.0000001);
	}
	return Math.floor(floatNum+0.0000001);
}
/** Start: Holds arabic and englsih month names**/
//return English month full name
function getEnglishMonthFullName(month) {
	var monthName = new Array('January', 'February', 'March', 'April', 'May', 'June',
					'July', 'August', 'September', 'October', 'November', 'December');
	return monthName[month];
}

//return English month full name
function getEnglishMonthShortName(month) {
	var monthName = new Array('Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
					'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec');
	return monthName[month];
}

function getHijriMonthFullName(month) {
	var monthName = new Array('Muharram', 'Safar', 'Rabi Al-Awwal', 'Rabi Al-Thani', 'Jumada Al-Awwal', 'Jumada Al-Thani' , 'Rajab', 'Sha`ban', 'Ramadan', 'Shawwal', 'Dhul-Qa`dah', 'Dhul-Hijjah');
	return monthName[month];
}

function getHijriMonthName(month) {
	var monthName = new Array('Muharram', 'Safar', 'Rabi Al-Awwal', 'Rabi Al-Thani', 'Jumada Al-Awwal', 'Jumada Al-Thani' , 'Rajab', 'Sha`ban', 'Ramadan', 'Shawwal', 'Dhul-Qa`dah', 'Dhul-Hijjah');
	return monthName[month];
}

function getHijriMonthShortName(month) {
	var monthName = new Array('Muharram', 'Safar', 'Rabi Al-Awwal', 'Rabi Al-Thani', 'Jumada Al-Awwal', 'Jumada Al-Thani' , 'Rajab', 'Sha`ban', 'Ramadan', 'Shawwal', 'Dhul-Qa`dah', 'Dhul-Hijjah');
	return monthName[month];
}

HijriToGreg.js

/** set the offset **/
var delta = 1; // this may get overwritten on the fly by js functions in prayer.lib.js depending on hijri to greg and greg to hijri and the manually edited array values

function HijriToGreg(arabicDate) {
	console.log ( 'arabicDate' );
	console.log (arabicDate);

	if(arabicDate == ""){
		return "";
	}
  
	//declare a date format year,month,day sequence
	var jd;
	var jd1;
	var l;
	var j;
	var n;
	var wd;
	var i;
	var k;

	var d = parseInt(arabicDate[2]);
	var m = parseInt(arabicDate[1]);
	var y = parseInt(arabicDate[0]);
	
	var deltaAdjusted;
	deltaAdjusted = adjustDelta(m,y);

	var english_date = new Array(0,0,0);

	//added delta=1 on jd to comply isna rulling for hajj 2007
	//delta = delta_array_hijri[arabicDate[1] - 1];

	jd = intPart((11*y+3)/30)+354*y+30*m-intPart((m-1)/2)+d+1948440-385-deltaAdjusted;
	//arg.JD.value=jd
	//wd = weekDay(jd % 7); // no use of this line

	if (jd > 2299160 ) {
		l = jd + 68569;
		n = intPart((4*l)/146097);
		l = l - intPart((146097*n+3)/4);
		i = intPart((4000*(l+1))/1461001);
		l = l-intPart((1461*i)/4)+31;
		j = intPart((80*l)/2447);
		d = l-intPart((2447*j)/80);
		l = intPart(j/11);
		m = j+2-12*l;
		y = 100*(n-49)+i+l;
	}	else {
		j = jd+1402;
		k = intPart((j-1)/1461);
		l = j-1461*k;
		n = intPart((l-1)/365)-intPart(l/1461);
		i = l-365*n+30;
		j = intPart((80*i)/2447);
		d = i-intPart((2447*j)/80);
		i = intPart(j/11);
		m = j+2-12*i;
		y= 4*k+n+i-4716;
	}

	english_date[2] = d;
	english_date[1] = m;
	english_date[0] = y;

	return english_date;

}

usage.js

var nowDate = new Date();
var arabic_nowDate = GregToHijri(nowDate);
var monthsno = arabic_nowDate[1] <10 ?  "(0"+arabic_nowDate[1]+")" : "("+arabic_nowDate[1]+")";
var sm = getHijriMonthName(arabic_nowDate[1]-1)+monthsno+", "+arabic_nowDate[0];
	$("#prayerTimesByArabicMonth option:contains(" + sm + ")").attr('selected', 'selected');

var arabicStartDate = new Array(arabicCurrentYear,arabicCurrentMonth,1);
var english_equvant_start_date = HijriToGreg(arabicStartDate);