자바스크립트 달력

//달력 시작
function setStyle(id,style,value)
{
    id.style[style] = value;
}

function calendar()
{
        var date = new Date();
        var day = date.getDate();
        var month = date.getMonth();
        var year = date.getYear();
        if(year<=200)
        {
                year += 1900;
        }
        months = new Array('1', '2', '3', '4', '5', '6', '7', '8', '9', '10', '11', '12');
        days_in_month = new Array(31,28,31,30,31,30,31,31,30,31,30,31);
        if(year%4 == 0 && year!=1900)
        {
                days_in_month[1]=29;
        }
        total = days_in_month[month];
        var date_today = year+'년'+months[month]+'월 '+day+'일';
        beg_j = date;
        beg_j.setDate(1);
        if(beg_j.getDate()==2)
        {
                beg_j=setDate(0);
        }
        beg_j = beg_j.getDay();
        document.write('<table class="cal_calendar" onload="<tbody id="cal_body"><tr><th colspan="7">'+date_today+'</th></tr>');
        document.write('<tr class="cal_d_weeks"><th>일</th><th>월</th><th>화</th><th>수</th><th>목</th><th>금</th><th>토</th></tr><tr>');
        week = 0;
        for(i=1;i<=beg_j;i++)
        {
                document.write('<td class="cal_days_bef_aft">'+(days_in_month[month-1]-beg_j+i)+'</td>');
                week++;
        }
        for(i=1;i<=total;i++)
        {
                if(week==0)
                {
                        document.write('<tr>');
                }
                if(day==i)
                {
                        document.write('<td class="cal_today" style="background-color:#e0e0e0;">'+i+'</td>');
                }
                else
                {
                        document.write('<td>'+i+'</td>');
                }
                week++;
                if(week==7)
                {
                        document.write('</tr>');
                        week=0;
                }
        }
        for(i=1;week!=0;i++)
        {
                document.write('<td class="cal_days_bef_aft">'+i+'</td>');
                week++;
                if(week==7)
                {
                        document.write('</tr>');
                        week=0;
                }
        }
        document.write('</tbody></table>');
      
        return true;
}
//달력 끝