// Project: Dynamic Date Selector (DtTvB) - 2006-03-16
// Script featured on JavaScript Kit- http://www.javascriptkit.com
// fixed bugs Apr 2009 GWW
// 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();
var currentdate = '';

// 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();">&lt;&lt;</td>'
     + '<td class="ds_head" style="cursor: pointer" onclick="ds_pm();">&lt;</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();">&gt;</td>'
     + '<td class="ds_head" style="cursor: pointer" onclick="ds_ny();">&gt;&gt;</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 mn = m-1;
  var ds_dc_date = new Date();
  ds_dc_date.setDate(1);
  ds_dc_date.setMonth(mn);
  ds_dc_date.setFullYear(y);
  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;
  currentdate =  ds_element.value;
  // 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 y + '-' + m2 + '-' + d2;
}

// 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);
      if(currentdate != ds_element.value)
    { RecordPageChange();}
  // 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));
  }
}
function RecordPageChange()
{
}