/** fix from date to be greater than actual date */
function fix_from_date()
{
	var from = new Date();
	var actual = new Date();

	from.setFullYear(document.getElementById('yearfrom').value, (Number(document.getElementById('monthfrom').value) - 1), document.getElementById('dayfrom').value);
	actual.setFullYear(2024,4,3);

	if(from.getTime() < actual.getTime())
	{
		document.getElementById('dayfrom').options[actual.getDate() - 1].selected = true;
		document.getElementById('monthfrom').options[actual.getMonth()].selected = true;
	}
}

/** fix number of days according to given month and year
*
* @param	string type type of date (from|to)
*/
function fix_days(type)
{
	if(type == 'from' || type == 'to')
	{
		var date = new Date();
		var day = 32;
		var month = Number(document.getElementById('month'+type).value) - 1;
		var year = document.getElementById('year'+type).value;
		var element = document.getElementById('day'+type);

		date.setFullYear(year, month, day);

		// find first correct day of the month
		do
		{
			day--;	
			date.setFullYear(year, month, day);
		}
		while(date.getMonth() > month);

		// find selected day
		var selected = null;
		for(i = 0; i < element.length; i++)
			if(element.options[i].selected)
			{
				selected = element.value;
				break;
			}

		// rebuild option list of days
		for(i = element.length - 1; i >= 0; i--)
			element.remove(i);

		for(i = 0; i < day; i++)
		{
			var option = document.createElement('OPTION');
			option.text = i + 1;
			option.value = i + 1;
			element.options.add(option);
		}

		// correct selected day
		if(selected != null && day < selected)
			selected = day;

		if(selected != null)
			element.options[selected - 1].selected = true;
	}
}