تحويل التاريخ بين التقويمين الهجري و الميلادي مباشر من هنا

function intPart(floatNum){
if (floatNum< -0.0000001){
return Math.ceil(floatNum-0.0000001)
}
return Math.floor(floatNum+0.0000001)
}
function weekDay(wdn){
if(wdn==0){
return "الأثنين"
}
if(wdn==1){
return "الثلاثاء"
}
if(wdn==2){
return "الإربعاء"
}
if(wdn==3){
return "الخميس"
}
if(wdn==4){
return "الجمعه"
}
if(wdn==5){
return "السبت"
}
if(wdn==6){
return "الأحد"
}
return ""
}
function chrToIsl(arg) {
d=parseInt(arg.CDay.value)
m=parseInt(arg.CMonth.value)
y=parseInt(arg.CYear.value)
if ((y>1582)||((y==1582)&&(m>10))||((y==1582)&&(m==10)&&(d>14)))
{
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
}
else
{
jd = 367*y-intPart((7*(y+5001+intPart((m-9)/7)))/4)+intPart((275*m)/9)+d+1729777
}
arg.JD.value=jd
arg.wd.value=weekDay(jd%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
arg.HDay.value=d
arg.HMonth.value=m
arg.HYear.value=y
}
function islToChr(arg) {
d=parseInt(arg.HDay.value)
m=parseInt(arg.HMonth.value)
y=parseInt(arg.HYear.value)
jd=intPart((11*y+3)/30)+354*y+30*m-intPart((m-1)/2)+d+1948440-385
arg.JD.value=jd
arg.wd.value=weekDay(jd%7)
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
}
arg.CDay.value=d
arg.CMonth.value=m
arg.CYear.value=y
}
function cls(arg) {
d=""
m=""
y=""
arg.CDay.value=d
arg.CMonth.value=m
arg.CYear.value=y
arg.HDay.value=d
arg.HMonth.value=m
arg.HYear.value=y
arg.JD.value=""
arg.wd.value=""
}