function cal_to_jd( era, y, m, d, h, mn, s )
        {
	        
		//alert("Cal " + h);
                if( y == 0 ) 
                {        
                   alert("There is no year 0 in the Julian system!");
                   return "invalid";
                }   
                if( y == 1582 && m == 10 && d > 4 && d < 15 ) 
                {               
                    alert("The dates 5 through 14 October, 1582, do not exist in the Gregorian system!");
                    return "invalid";    
                }            
                
                if( era == "BCE" )
                { 
                    y = -y + 1;
                }

                //added by me 
                var jy;
                var jm;
                
                if( m > 2 ) 
                {
                    jy = y;
                    jm = m + 1;
                }
                else 
                {               
                    jy = y - 1;
                    jm = m + 13;
                }
                
                var intgr = Math.floor( Math.floor(365.25*jy) + Math.floor(30.6001*jm) + d + 1720995 );
                //check for switch to Gregorian calendar
                var gregcal = 15 + 31*( 10 + 12*1582 );
                if( d + 31*(m + 12*y) >= gregcal ) 
                {               
                        ja = Math.floor(0.01*jy);                        
                        intgr += 2 - ja + Math.floor(0.25*ja);
                }
                //correct for half-day offset
                var dayfrac = h/24.0 - 0.5;
        
                if( dayfrac < 0.0 )  
                {               
                    dayfrac += 1.0;
                     --intgr;
                }
                //now set the fraction of a day 
                var frac = dayfrac + (mn + s/60.0)/60.0/24.0;
                //round to nearest second
                var jd0 = (intgr + frac)*100000;
                var jd  = Math.floor(jd0);
                if( jd0 - jd > 0.5 )
                {
                   ++jd;
                }
                var myvar = jd/100000;
                return myvar;       
     } 
     
     //julian date to calendar date
     function jd_to_cal( jd)
     {  

         var j1, j2, j3, j4,j5;  //scratch              
        // get the date from the Julian day number
        //
        var intgr   = Math.floor(jd);
        var frac    = jd - intgr;
        var gregjd  = 2299161;
        if( intgr >= gregjd ) 
        {               
              //Gregorian calendar correction
              var tmp = Math.floor( ( (intgr - 1867216) - 0.25 ) / 36524.25 )
              j1 = intgr + 1 + tmp - Math.floor(0.25*tmp);      
        }     
        else
        j1 = intgr; 
        //correction for half day offset
        var dayfrac = frac + 0.5;

        
        if( dayfrac >= 1.0 ) 
        {                       
             dayfrac -= 1.0;
             ++j1;                                            
        }
        
        j2 = j1 + 1524;                                                 
        j3 = Math.floor( 6680.0 + ( (j2 - 2439870) - 122.1 )/365.25 );
        j4 = Math.floor(j3*365.25);
        j5 = Math.floor( (j2 - j4)/30.6001 );
        var d = Math.floor(j2 - j4 - Math.floor(j5*30.6001));
        var m = Math.floor(j5 - 1);
        if( m > 12 ) m -= 12;
        var y = Math.floor(j3 - 4715);
        if( m > 2 )   --y;
        if( y <= 0 )  --y;
        //
        // get time of day from day fraction
        //      
        var hr  = Math.floor(dayfrac * 24.0);
        var mn = Math.floor((dayfrac*24.0 - hr)*60.0);
        f  = ((dayfrac*24.0 - hr)*60.0 - mn)*60.0;
        var sc  = Math.floor(f);
        f -= sc;
        if( f > 0.5 ) ++sc;
        if( y < 0 ) 
        {  
                y = -y;
                //form.era[1].checked = true;
        }
        array = new Array(y,m,d,hr,mn,sc);
        return array;
     }