function showCalendar (img, cal, dt, frm,m,y,d){
    if (document.getElementById){
        var c = document.getElementById(cal);
        var i = document.getElementById(img);
        var f = document.getElementById(frm);
        calendar.calfrm = frm;
        calendar.cal = c;
        calendar.caldt = dt;
        calendar.calf = f;
        var my = f[dt + '_month'].value.split("-");
        y=my[0];m=my[1];d=f[ dt + '_day'].value;
        buildCal(y,m,d);
        var l=0; var t=0;
        aTag = i;
        do {
            aTag = aTag.offsetParent;
            l += aTag.offsetLeft;
            t += aTag.offsetTop;
        } while (aTag.offsetParent && aTag.tagName != 'BODY');
        
        var left =  i.offsetLeft + l;
        var top = i.offsetTop + t + i.offsetHeight + 4;
        c.style.left = left+'px';
        c.style.top = top+'px';
        c.style.display="block";
	}
}

function closeCal() {
    calendar.cal.style.display='none';
    /*if (navigator.appName == "Microsoft Internet Explorer") 
    	toggleSelects('visible'); */
}

function buildCal(y,m,d){
    var daysInMonth=[31,0,31,30,31,30,31,31,30,31,30,31];
    td=new Date();
    td.setUTCDate(td.getUTCDate()+1);
    if (!y) y = td.getFullYear();
    if (!m) m = td.getMonth()+1;
    if (!d) d = td.getDate;
	var frm = calendar.calfrm;
    var dt = calendar.caldt;

    var mDate = new Date(y, m-1, 1);
    var firstMonthDay = mDate.getDay();
    daysInMonth[1]=(((mDate.getFullYear()%100!=0)
        &&(mDate.getFullYear()%4==0)) || (mDate.getFullYear()%400==0))?29:28;

    var t='<table class="caltable" cellspacing="0"><tr>';
    t+='<td class="calheader" colspan="7" class="monthYear">';
    if (y==td.getFullYear() && m==td.getMonth()+1) {
        t+='<b>&#171;</b>';
    }
    else {
        t+='<a class="calPrevMonth" href="" onclick="prevMonth('+y+','+m+'); return false;" title="'+tr.prevMonth+'"><b>&#171;</b></a>';
    }
    t+='&nbsp;<select name="ym" onchange="goYearMonth(this.options[this.selectedIndex].value)" class="select">';
    var mn=td.getMonth()+1;var yr=td.getFullYear();
    var last_month=0;
    for(n=0;n<=11;n++){
        t+='<option value="' + yr + '-' + mn + '"';
        if (mn == m && yr == y) {
            t+=' selected="selected"';
            last_month=1;
        } else {
            last_month=0;
        }
        t+='>' + months[mn-1] + ' ' + yr +'</option>';
        mn++; if (mn>12) { mn=1;yr++ }
    }
    t+= ' </select>&nbsp;';
    if (last_month==1) {
        t+='<b>&#187;</b>';
    }
    else {
        t+='<a class="calNextMonth" href="" onclick="nextMonth('+y+','+m+'); return false;" title="' + tr.nextMonth +'"><b>&#187;</b></a>';
    }
    t+='</td></tr>';
    t+='<tr class="dayNames">';
    for(dn=0;dn<7;dn++){
        var cl = '';
        if ((dn%7==5) || (dn%7 == 6)) cl += ' weekend';
        t+='<td class="'+cl+'">'+days[dn]+'</td>';
    }
    t+='</tr><tr class="days">';
    for(i=1;i<=42;i++){
        var x = i - (firstMonthDay+6)%7;
        if (x > daysInMonth[m-1] || x <1) x = '&nbsp;';
        var cl = '';
        var href = 0;
        if ((i%7==0) || (i%7 == 6)) cl += ' weekend';
        if (x>0){
            var xDay = new Date(y, m-1, x);
            if ((xDay.getFullYear() == y) && (xDay.getMonth()+1 == m)
                && (xDay.getDate() == d))
                { cl += ' selected' ; href=1}
            if ((xDay.getFullYear() == td.getFullYear())
                && (xDay.getMonth() == td.getMonth())
                && (xDay.getDate() == td.getDate()))
                { cl += ' today'; href=1;}
            else {
                if (xDay > td){ cl += ' future'; href=1; }
                else {
                    if (xDay < td) { cl += ' past'}
                }
            }
        };
        t+='<td class="'+cl+'">';
        if (href){
            t+='<a href="#" onclick="pickDate('+y+','+m+','+x+',\''+dt+'\',\''+frm+'\'); return false;">'+x+'</a>';
        } else {
            t+=x;
        }
        t+='</td>';
        if(((i)%7==0)&&(i<36)) {
            t+='</tr><tr class="days">';
        }
    }
    t+='</tr><tr><td colspan="7"><b><a href="#" onclick="closeCal();return false;">' + tr.closeCalendar + '</a></b></td></tr></table>';
    document.getElementById("calendar").innerHTML= t;
    
    /*if (navigator.appName == "Microsoft Internet Explorer") 
    	toggleSelects('hidden'); */
}

function prevMonth(y,m) {
    if (new Date(y,m-1,1) < td) return;
    if (m > 1) {m--} else {m = 12; y--};
    buildCal(y,m);
}

//does this finction need to check for max month/year?
function nextMonth(y,m) {
    if (m<12){m++;} else {m=1;y++;}
    buildCal(y,m);
}

function goYearMonth(ym){
	var ymlist = ym.split("-");
    buildCal(ymlist[0],ymlist[1]);
}

function pickDate(y,m,d,dt,frm){
    // set form values
    var f = calendar.calf;
    var dt = calendar.caldt;
    f[dt + '_month'].value = y + "-"  + m;
    f[dt + '_day'].value = d;
	if (dt == "checkin"){
		checkDateOrder(calendar.calfrm, 'checkin_day', 'checkin_month', 'checkout_day', 'checkout_month');
	}
    closeCal();
}

function checkDateOrder(frm, ci_day, ci_month_year, co_day, co_month_year) {
	if (document.getElementById) {

		var frm = document.getElementById(frm);
		// create date object from checkin values
		// set date to 12:00 to avoid problems with one
		// date being wintertime and the other summertime
		var my = frm[ci_month_year].value.split("-");
	    var ci = new Date (my[0], my[1]-1, frm[ci_day].value, 12, 0, 0, 0);

        // create date object from checkout values
	    my = frm[co_month_year].value.split("-");
	    var co = new Date (my[0], my[1]-1, frm[co_day].value, 12, 0, 0, 0);


		// if checkin date is at or after checkout date,
		// add a day full of milliseconds, and set the
		// selectbox values for checkout date to new value
	    if (ci >= co){
    	    co.setTime(ci.getTime() + 1000 * 60 * 60 * 24);
	        frm[co_day].value =  co.getDate();
    	    var com = co.getMonth()+1;
	        frm[co_month_year].value = co.getFullYear() + "-" + com;
    	}
	}
}

function toggleSelects(state) 
{
	var d = document;
/*	for (var i=0; (sel=d.getElementsByTagName('select')[i]); i++) {
		sel.style.visibility = state;
		}
	*/	
	for (var i=0; (sel=d.getElementById('book_avil_id_'+i)); i++) {
		sel.style.visibility = state;
		}
}