calendar.js

// Project: Dynamic Date Selector (DtTvB) - 2006-03-16
// Script featured on JavaScript Kit- http://www.javascriptkit.com
// Code begin...
// Set the initial date.
var ds_i_date = new Date();
ds_c_month = ds_i_date.getMonth() + 1;
ds_c_year = ds_i_date.getFullYear();

// Get Element By Id
function ds_getel(id) {
    return document.getElementById(id);
}

// Get the left and the top of the element.
function ds_getleft(el) {
    var tmp = el.offsetLeft;
    el = el.offsetParent
    while(el) {
        tmp += el.offsetLeft;
        el = el.offsetParent;
    }
    return tmp;
}
function ds_gettop(el) {
    var tmp = el.offsetTop;
    el = el.offsetParent
    while(el) {
        tmp += el.offsetTop;
        el = el.offsetParent;
    }
    return tmp;
}

// Output Element
var ds_oe = ds_getel('ds_calclass');
// Container
var ds_ce = ds_getel('ds_conclass');

// Output Buffering
var ds_ob = '';
function ds_ob_clean() {
    ds_ob = '';
}
function ds_ob_flush() {
    ds_oe.innerHTML = ds_ob;
    ds_ob_clean();
}
function ds_echo(t) {
    ds_ob += t;
}

var ds_element; // Text Element...

var ds_monthnames = [
'January', 'February', 'March', 'April', 'May', 'June',
'July', 'August', 'September', 'October', 'November', 'December'
]; // You can translate it for your language.

var ds_daynames = [
'Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'
]; // You can translate it for your language.

// Calendar template
function ds_template_main_above(t) {
    return '<table cellpadding="3" cellspacing="1" class="ds_tbl">'
         + '<tr>'
         + '<td class="ds_head" style="cursor: pointer" onclick="ds_py();"><<</td>'
         + '<td class="ds_head" style="cursor: pointer" onclick="ds_pm();"><</td>'
         + '<td class="ds_head" style="cursor: pointer" onclick="ds_hi();" colspan="3">[Close]</td>'
         + '<td class="ds_head" style="cursor: pointer" onclick="ds_nm();">></td>'
         + '<td class="ds_head" style="cursor: pointer" onclick="ds_ny();">>></td>'
         + '</tr>'
         + '<tr>'
         + '<td colspan="7" class="ds_head">' + t + '</td>'
         + '</tr>'
         + '<tr>';
}

function ds_template_day_row(t) {
    return '<td class="ds_subhead">' + t + '</td>';
    // Define width in CSS, XHTML 1.0 Strict doesn't have width property for it.
}

function ds_template_new_week() {
    return '</tr><tr>';
}

function ds_template_blank_cell(colspan) {
    return '<td colspan="' + colspan + '"></td>'
}

function ds_template_day(d, m, y) {
    return '<td class="ds_cell" onclick="ds_onclick(' + d + ',' + m + ',' + y + ')">' + d + '</td>';
    // Define width the day row.
}

function ds_template_main_below() {
    return '</tr>'
         + '</table>';
}

// This one draws calendar...
function ds_draw_calendar(m, y) {
    // First clean the output buffer.
    ds_ob_clean();
    // Here we go, do the header
    ds_echo (ds_template_main_above(ds_monthnames[m - 1] + ' ' + y));
    for (i = 0; i < 7; i ++) {
        ds_echo (ds_template_day_row(ds_daynames[i]));
    }
    // Make a date object.
    var ds_dc_date = new Date();
    ds_dc_date.setMonth(m - 1);
    ds_dc_date.setFullYear(y);
    ds_dc_date.setDate(1);
    if (m == 1 || m == 3 || m == 5 || m == 7 || m == 8 || m == 10 || m == 12) {
        days = 31;
    } else if (m == 4 || m == 6 || m == 9 || m == 11) {
        days = 30;
    } else {
        days = (y % 4 == 0) ? 29 : 28;
    }
    var first_day = ds_dc_date.getDay();
    var first_loop = 1;
    // Start the first week
    ds_echo (ds_template_new_week());
    // If sunday is not the first day of the month, make a blank cell...
    if (first_day != 0) {
        ds_echo (ds_template_blank_cell(first_day));
    }
    var j = first_day;
    for (i = 0; i < days; i ++) {
        // Today is sunday, make a new week.
        // If this sunday is the first day of the month,
        // we've made a new row for you already.
        if (j == 0 && !first_loop) {
            // New week!!
            ds_echo (ds_template_new_week());
        }
        // Make a row of that day!
        ds_echo (ds_template_day(i + 1, m, y));
        // This is not first loop anymore...
        first_loop = 0;
        // What is the next day?
        j ++;
        j %= 7;
    }
    // Do the footer
    ds_echo (ds_template_main_below());
    // And let's display..
    ds_ob_flush();
    // Scroll it into view.
    ds_ce.scrollIntoView();
}

// A function to show the calendar.
// When user click on the date, it will set the content of t.
function ds_sh(t) {
    // Set the element to set...
    ds_element = t;
    // Make a new date, and set the current month and year.
    var ds_sh_date = new Date();
    ds_c_month = ds_sh_date.getMonth() + 1;
    ds_c_year = ds_sh_date.getFullYear();
    // Draw the calendar
    ds_draw_calendar(ds_c_month, ds_c_year);
    // To change the position properly, we must show it first.
    ds_ce.style.display = '';
    // Move the calendar container!
    the_left = ds_getleft(t);
    the_top = ds_gettop(t) + t.offsetHeight;
    ds_ce.style.left = the_left + 'px';
    ds_ce.style.top = the_top + 'px';
    // Scroll it into view.
    ds_ce.scrollIntoView();
}

// Hide the calendar.
function ds_hi() {
    ds_ce.style.display = 'none';
}

// Moves to the next month...
function ds_nm() {
    // Increase the current month.
    ds_c_month ++;
    // We have passed December, let's go to the next year.
    // Increase the current year, and set the current month to January.
    if (ds_c_month > 12) {
        ds_c_month = 1;
        ds_c_year++;
    }
    // Redraw the calendar.
    ds_draw_calendar(ds_c_month, ds_c_year);
}

// Moves to the previous month...
function ds_pm() {
    ds_c_month = ds_c_month - 1; // Can't use dash-dash here, it will make the page invalid.
    // We have passed January, let's go back to the previous year.
    // Decrease the current year, and set the current month to December.
    if (ds_c_month < 1) {
        ds_c_month = 12;
        ds_c_year = ds_c_year - 1; // Can't use dash-dash here, it will make the page invalid.
    }
    // Redraw the calendar.
    ds_draw_calendar(ds_c_month, ds_c_year);
}

// Moves to the next year...
function ds_ny() {
    // Increase the current year.
    ds_c_year++;
    // Redraw the calendar.
    ds_draw_calendar(ds_c_month, ds_c_year);
}

// Moves to the previous year...
function ds_py() {
    // Decrease the current year.
    ds_c_year = ds_c_year - 1; // Can't use dash-dash here, it will make the page invalid.
    // Redraw the calendar.
    ds_draw_calendar(ds_c_month, ds_c_year);
}

// Format the date to output.
function ds_format_date(d, m, y) {
    // 2 digits month.
    m2 = '00' + m;
    m2 = m2.substr(m2.length - 2);
    // 2 digits day.
    d2 = '00' + d;
    d2 = d2.substr(d2.length - 2);
    // YYYY-MM-DD
    return m2+':'+d2+':'+y.toString().substr(2,2);
}

// When the user clicks the day.
function ds_onclick(d, m, y) {
    // Hide the calendar.
    ds_hi();
    // Set the value of it, if we can.
    if (typeof(ds_element.value) != 'undefined') {
        ds_element.value = ds_format_date(d, m, y);
    // Maybe we want to set the HTML in it.
    } else if (typeof(ds_element.innerHTML) != 'undefined') {
        ds_element.innerHTML = ds_format_date(d, m, y);
    // I don't know how should we display it, just alert it to user.
    } else {
        alert (ds_format_date(d, m, y));
    }
}