How to change Gregorian date to Persian date in JavaScript?

Question

Can anyone help me to change Gregorian date to Persian in JavaScript? I want to use it in HTML and JavaScript.

Answer 1

non of answers in this page worked correct, its working in some cases but not always correct! this is working both side converting methods :

function gregorian_to_jalali(gy,gm,gd){
        var g_d_m=[0,31,59,90,120,151,181,212,243,273,304,334];
        var jy=(gy<=1600)?0:979;
        gy-=(gy<=1600)?621:1600;
        var gy2=(gm>2)?(gy+1):gy;
        var days=(365*gy) +(parseInt((gy2+3)/4)) -(parseInt((gy2+99)/100))
                +(parseInt((gy2+399)/400)) -80 +gd +g_d_m[gm-1];
        jy+=33*(parseInt(days/12053));
        days%=12053;
        jy+=4*(parseInt(days/1461));
        days%=1461;
        jy+=parseInt((days-1)/365);
        if(days > 365)days=(days-1)%365;
        var jm=(days < 186)?1+parseInt(days/31):7+parseInt((days-186)/30);
        var jd=1+((days < 186)?(days%31):((days-186)%30));
        return [jy,jm,jd];
    }
function jalali_to_gregorian(jy,jm,jd){
        var gy=(jy<=979)?621:1600;
        jy-=(jy<=979)?0:979;
        var days=(365*jy) +((parseInt(jy/33))*8) +(parseInt(((jy%33)+3)/4))
                +78 +jd +((jm<7)?(jm-1)*31:((jm-7)*30)+186);
        gy+=400*(parseInt(days/146097));
        days%=146097;
        if(days > 36524){
            gy+=100*(parseInt(--days/36524));
            days%=36524;
            if(days >= 365)days++;
        }
        gy+=4*(parseInt((days)/1461));
        days%=1461;
        gy+=parseInt((days-1)/365);
        if(days > 365)days=(days-1)%365;
        var gd=days+1;
        var sal_a=[0,31,((gy%4==0 && gy%100!=0) || (gy%400==0))?29:28,31,30,31,30,31,31,30,31,30,31];
        var gm
        for(gm=0;gm<13;gm++){
            var v=sal_a[gm];
            if(gd <= v)break;
            gd-=v;
        }
        return [gy,gm,gd];
    }

code from : https://github.com/hat3ck/Persian-Calendar-Qt