CIS 119 Create current month calendar

Source code

var month = new Array('January', 'February', 'March',
    'April', 'May', 'June', 'July', 'August', 'September',
    'October', 'November', 'December');
var days = new Array('Sun', 'Mon', 'Tue', 'Wed',
    'Thu', 'Fri', 'Sat');
var now = new Date();
var ctr;

document.writeln('<table>');
document.writeln('<caption align="top"><h3>' +
    month[now.getMonth()] + ' ' + now.getFullYear() +
    '</h3></caption>');
document.write('<tr>');
for (ctr=0; ctr<7; ctr++) {
    document.write('<th width="14%">' + days[ctr] + '</th>');
}
document.writeln('</tr>');
var d0 = new Date(now.getFullYear(), now.getMonth(), 1);

document.write('<tr align="right">');
ctr = d0.getDay();
while (ctr-- > 0) {
    document.write('<td> </td>');
}
while (d0.getMonth() == now.getMonth()) {
    var d = d0.getDate();
    if (d0.getDate() != now.getDate()) {
        document.write('<td>' + d + '</td>');
    } else {
        document.write('<td bgcolor="yellow" style="color:#0000ff;font-weight:bold">' + d + '</td>');
    }
    d0.setDate(d0.getDate() + 1);
    if (d0.getDay() == 0) {
        document.writeln('</tr>');
        if (d0.getMonth() == now.getMonth()) {
            document.write('<tr align="right">');
        }
    }
}

if (d0.getDay() != 0) {
    ctr = 7 - d0.getDay();
    while (ctr-- > 0) {
        document.write('<td> </td>');
    }
    document.writeln('</tr>');
}

document.writeln('</table>');