calendar = {
	month_names: ["January","February","March","April","May","June","July","Augest","September","October","November","December"],
	weekdays: ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"],
	month_days: [31,28,31,30,31,30,31,31,30,31,30,31],
	//Get today's date - year, month, day and date
	today : new Date(),
	opt : {},
	data: [],

	//Functions
	/// Used to create HTML in a optimized way.
	wrt:function(txt) {
		this.data.push(txt);
	},
	
		getStyle: function(ele, property){
		if (ele.currentStyle) {
			var alt_property_name = property.replace(/\-(\w)/g,function(m,c){return c.toUpperCase();});//background-color becomes backgroundColor
			var value = ele.currentStyle[property]||ele.currentStyle[alt_property_name];
		
		} else if (window.getComputedStyle) {
			property = property.replace(/([A-Z])/g,"-$1").toLowerCase();//backgroundColor becomes background-color

			var value = document.defaultView.getComputedStyle(ele,null).getPropertyValue(property);
		}
		
		//Some properties are special cases
		if(property == "opacity" && ele.filter) value = (parseFloat( ele.filter.match(/opacity\=([^)]*)/)[1] ) / 100);
		else if(property == "width" && isNaN(value)) value = ele.clientWidth || ele.offsetWidth;
		else if(property == "height" && isNaN(value)) value = ele.clientHeight || ele.offsetHeight;
		return value;
	},
	getPosition:function(ele) {
		var x = 0;
		var y = 0;
		while (ele) {
			x += ele.offsetLeft;
			y += ele.offsetTop;
			ele = ele.offsetParent;
		}
		if (navigator.userAgent.indexOf("Mac") != -1 && typeof document.body.leftMargin != "undefined") {
			x += document.body.leftMargin;
			offsetTop += document.body.topMargin;
		}
	
		var xy = new Array(x,y);
		return xy;
	},
	/// Called when the user clicks on a date in the calendar.
	selectDate:function(year,month,day) {
		var ths = _calendar_active_instance;
		document.getElementById(ths.opt["input"]).value = month + "/" + day + "/" + year; // Date format is :HARDCODE:
		ths.hideCalendar();

},

///Start Modification By Rupesh
/// Called when the user clicks on a date in the calendar.
selectDateMultiple: function(year, month, day) {
    var ths = _calendar_active_instance;
    if (document.getElementById(ths.opt["input"]).value == "" || document.getElementById(ths.opt["input"]).value == " ") {
        document.getElementById(ths.opt["input"]).value = month+"/"+day+"/"+year; // Date format is :HARDCODE:
    }
    
    else {
        var objstr = month + "/" + day + "/" + year; 
        if (document.getElementById(ths.opt["input"]).value.indexOf(objstr) < 0) {
            document.getElementById(ths.opt["input"]).value += ";" + objstr;
        }
    }
    //ths.hideCalendar();

},
///End Modification By Rupesh

	
	/// Creates a calendar with the date given in the argument as the selected date.
	makeCalendar:function(year, month, day) {
		year = parseInt(year);
		month= parseInt(month);
		day	 = parseInt(day);
		
		//Display the table
		var next_month = month+1;
		var next_month_year = year;
		if(next_month>=12) {
			next_month = 0;
			next_month_year++;
		}
		
		var previous_month = month-1;
		var previous_month_year = year;
		if(previous_month< 0) {
			previous_month = 11;
			previous_month_year--;
		}
		
		this.wrt("<table>");
		this.wrt("<tr><th><a href='javascript:calendar.makeCalendar("+(previous_month_year)+","+(previous_month)+");' title='"+this.month_names[previous_month]+" "+(previous_month_year)+"'>&lt;</a></th>");
		this.wrt("<th colspan='5' class='calendar-title'><select name='calendar-month' class='calendar-month' onChange='calendar.makeCalendar("+year+",this.value);'>");
		for(var i in this.month_names) {
			this.wrt("<option value='"+i+"'");
			if(i == month) this.wrt(" selected='selected'");
			this.wrt(">"+this.month_names[i]+"</option>");
		}
		this.wrt("</select>");
		this.wrt("<select name='calendar-year' class='calendar-year' onChange='calendar.makeCalendar(this.value, "+month+");'>");
		var current_year = this.today.getYear();
		if(current_year < 1900) current_year += 1900;
		
		for(var i=current_year-70; i<current_year+10; i++) {
			this.wrt("<option value='"+i+"'")
			if(i == year) this.wrt(" selected='selected'");
			this.wrt(">"+i+"</option>");
		}
		this.wrt("</select></th>");
		this.wrt("<th><a href='javascript:calendar.makeCalendar("+(next_month_year)+","+(next_month)+");' title='"+this.month_names[next_month]+" "+(next_month_year)+"'>&gt;</a></th></tr>");
		this.wrt("<tr class='header'>");
		for(var weekday=0; weekday<7; weekday++) this.wrt("<td>"+this.weekdays[weekday]+"</td>");
		this.wrt("</tr>");
		
		//Get the first day of this month
		var first_day = new Date(year,month,1);
		var start_day = first_day.getDay();
		
		var d = 1;
		var flag = 0;
		
		//Leap year support
		if(year % 4 == 0) this.month_days[1] = 29;
		else this.month_days[1] = 28;
		
		var days_in_this_month = this.month_days[month];

		//Create the calender
		for(var i=0;i<=5;i++) {
			if(w >= days_in_this_month) break;
			this.wrt("<tr>");
			for(var j=0;j<7;j++) {
				if(d > days_in_this_month) flag=0; //If the days has overshooted the number of days in this month, stop writing
				else if(j >= start_day && !flag) flag=1;//If the first day of this month has come, start the date writing

				if(flag) {
					var w = d, mon = month+1;
					if(w < 10)	w	= "0" + w;
					if(mon < 10)mon = "0" + mon;

					//Is it today?
					var class_name = '';
					var yea = this.today.getYear();
					if(yea < 1900) yea += 1900;

					if(yea == year && this.today.getMonth() == month && this.today.getDate() == d) class_name = " today";
					if(day == d) class_name += " selected";
					
					class_name += " " + this.weekdays[j].toLowerCase();

					this.wrt("<td class='days"+class_name+"'><a href='javascript:calendar.selectDate(\""+year+"\",\""+mon+"\",\""+w+"\")'>"+w+"</a></td>");
					d++;
				} else {
					this.wrt("<td class='days'>&nbsp;</td>");
				}
			}
			this.wrt("</tr>");
		}
		this.wrt("</table>");
		this.wrt("<input type='button' value='Cancel' class='calendar-cancel' onclick='calendar.hideCalendar();' />");

		document.getElementById(this.opt['calendar']).innerHTML = this.data.join("");
		this.data = [];
},

///Start Modification By Rupesh
/// Creates a calendar(for Multiple date) with the date given in the argument as the selected date.
makeCalendarMultiple: function(year, month, day) {
    year = parseInt(year);
    month = parseInt(month);
    day = parseInt(day);

    //Display the table
    var next_month = month + 1;
    var next_month_year = year;
    if (next_month >= 12) {
        next_month = 0;
        next_month_year++;
    }

    var previous_month = month - 1;
    var previous_month_year = year;
    if (previous_month < 0) {
        previous_month = 11;
        previous_month_year--;
    }

    this.wrt("<table>");
    this.wrt("<tr><th><a href='javascript:calendar.makeCalendarMultiple(" + (previous_month_year) + "," + (previous_month) + ");' title='" + this.month_names[previous_month] + " " + (previous_month_year) + "'>&lt;</a></th>");
    this.wrt("<th colspan='5' class='calendar-title'><select name='calendar-month' class='calendar-month' onChange='calendar.makeCalendarMultiple(" + year + ",this.value);'>");
    for (var i in this.month_names) {
        this.wrt("<option value='" + i + "'");
        if (i == month) this.wrt(" selected='selected'");
        this.wrt(">" + this.month_names[i] + "</option>");
    }
    this.wrt("</select>");
    this.wrt("<select name='calendar-year' class='calendar-year' onChange='calendar.makeCalendarMultiple(this.value, " + month + ");'>");
    var current_year = this.today.getYear();
    if (current_year < 1900) current_year += 1900;

    for (var i = current_year - 70; i < current_year + 10; i++) {
        this.wrt("<option value='" + i + "'")
        if (i == year) this.wrt(" selected='selected'");
        this.wrt(">" + i + "</option>");
    }
    this.wrt("</select></th>");
    this.wrt("<th><a href='javascript:calendar.makeCalendarMultiple(" + (next_month_year) + "," + (next_month) + ");' title='" + this.month_names[next_month] + " " + (next_month_year) + "'>&gt;</a></th></tr>");
    this.wrt("<tr class='header'>");
    for (var weekday = 0; weekday < 7; weekday++) this.wrt("<td>" + this.weekdays[weekday] + "</td>");
    this.wrt("</tr>");

    //Get the first day of this month
    var first_day = new Date(year, month, 1);
    var start_day = first_day.getDay();

    var d = 1;
    var flag = 0;

    //Leap year support
    if (year % 4 == 0) this.month_days[1] = 29;
    else this.month_days[1] = 28;

    var days_in_this_month = this.month_days[month];

    //Create the calender
    for (var i = 0; i <= 5; i++) {
        if (w >= days_in_this_month) break;
        this.wrt("<tr>");
        for (var j = 0; j < 7; j++) {
            if (d > days_in_this_month) flag = 0; //If the days has overshooted the number of days in this month, stop writing
            else if (j >= start_day && !flag) flag = 1; //If the first day of this month has come, start the date writing

            if (flag) {
                var w = d, mon = month + 1;
                if (w < 10) w = "0" + w;
                if (mon < 10) mon = "0" + mon;

                //Is it today?
                var class_name = '';
                var yea = this.today.getYear();
                if (yea < 1900) yea += 1900;

                if (yea == year && this.today.getMonth() == month && this.today.getDate() == d) class_name = " today";
                if (day == d) class_name += " selected";

                class_name += " " + this.weekdays[j].toLowerCase();

                this.wrt("<td class='days" + class_name + "'><a href='javascript:calendar.selectDateMultiple(\"" + year + "\",\"" + mon + "\",\"" + w + "\")'>" + w + "</a></td>");
                d++;
            } else {
                this.wrt("<td class='days'>&nbsp;</td>");
            }
        }
        this.wrt("</tr>");
    }
    this.wrt("</table>");
    this.wrt("<input type='button' value='Ok' class='calendar-cancel okbtn' onclick='calendar.hideCalendar();' /><input type='button' value='Cancel' class='calendar-cancel' onclick='calendar.hideCalendar();' />");

    document.getElementById(this.opt['calendar']).innerHTML = this.data.join("");
    this.data = [];
},

///End Modification By Rupesh
	
	/// Display the calendar - if a date exists in the input box, that will be selected in the calendar.
	showCalendar: function() {
	   	var input = document.getElementById(this.opt['input']);
		
		//Position the div in the correct location...
		var div = document.getElementById(this.opt['calendar']);
		var xy = this.getPosition(input);
		var width = parseInt(this.getStyle(input,'width'));
		//div.style.left=(xy[0]+width-20)+"px";
		div.style.left=xy[0]+"px";
		div.style.top=xy[1]+"px";


		// Show the calendar with the date in the input as the selected date
		var existing_date = new Date();
		var date_in_input = input.value;
		if(date_in_input) {
			var selected_date = false;
			var date_parts = date_in_input.split("-");
			if(date_parts.length == 3) {
				date_parts[1]--; //Month starts with 0
				selected_date = new Date(date_parts[0], date_parts[1], date_parts[2]);
			}
			if(selected_date && !isNaN(selected_date.getYear())) { //Valid date.
				existing_date = selected_date;
			}
		}
		
		var the_year = existing_date.getYear();
		if(the_year < 1900) the_year += 1900;
		this.makeCalendar(the_year, existing_date.getMonth(), existing_date.getDate());
		document.getElementById(this.opt['calendar']).style.display = "block";
		_calendar_active_instance = this;
},


///Start Modification By Rupesh Nagar

/// Display the calendar(for multiple date selection) - if a date exists in the input box, that will be selected in the calendar.
showCalendarMultiple: function() {
    var input = document.getElementById(this.opt['input']);

    //Position the div in the correct location...
    var div = document.getElementById(this.opt['calendar']);
    var xy = this.getPosition(input);
    var width = parseInt(this.getStyle(input, 'width'));
    //div.style.left = (xy[0] + width + 10) + "px";
    div.style.left = xy[0] +  "px";
    div.style.top = xy[1] + "px";

    // Show the calendar with the date in the input as the selected date
    var existing_date = new Date();
    var date_in_input = input.value;
    if (date_in_input) {
        var selected_date = false;
        var date_parts = date_in_input.split("-");
        if (date_parts.length == 3) {
            date_parts[1]--; //Month starts with 0
            selected_date = new Date(date_parts[0], date_parts[1], date_parts[2]);
        }
        if (selected_date && !isNaN(selected_date.getYear())) { //Valid date.
            existing_date = selected_date;
        }
    }

    var the_year = existing_date.getYear();
    if (the_year < 1900) the_year += 1900;
    this.makeCalendarMultiple(the_year, existing_date.getMonth(), existing_date.getDate());
    document.getElementById(this.opt['calendar']).style.display = "block";
    _calendar_active_instance = this;
},
///End Modification By Rupesh Nagar
	
	/// Hides the currently show calendar.
	hideCalendar: function(instance) {
		var active_calendar_id = "";
		if(instance) active_calendar_id = instance.opt['calendar'];
		else active_calendar_id = _calendar_active_instance.opt['calendar'];
		
		if(active_calendar_id) document.getElementById(active_calendar_id).style.display = "none";
		_calendar_active_instance = {};
	},
	
	/// Setup a text input box to be a calendar box.
	set: function(input_id) {
		var input = document.getElementById(input_id);
		if(!input) return; //If the input field is not there, exit.
		
		if(!this.opt['calendar']) this.init();
		
		var ths = this;
		input.onfocus=function(){
			ths.opt['input'] = this.id;
			ths.showCalendar();
		};
},

///Start Modification By Rupesh Nagar
/// Setup a text input box to be a calendar box for multiple Date selection.
setMultiple: function(input_id) {
    var input = document.getElementById(input_id);
    if (!input) return; //If the input field is not there, exit.

    if (!this.opt['calendar']) this.init();

    var ths = this;
    input.onfocus = function() {
        ths.opt['input'] = this.id;
        ths.showCalendarMultiple();
    };
},
///End Modification By Rupesh Nagar


	/// Will be called once when the first input is set.
	init: function() {
		if(!this.opt['calendar'] || !document.getElementById(this.opt['calendar'])) {
			var div = document.createElement('div');
			if(!this.opt['calendar']) this.opt['calendar'] = 'calender_div_'+ Math.round(Math.random() * 100);

			div.setAttribute('id',this.opt['calendar']);
			div.className="calendar-box";

			document.getElementsByTagName("body")[0].insertBefore(div,document.getElementsByTagName("body")[0].firstChild);
		}
	}
}