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;
    	}
	}
}