/**
 * change day of birthday selector related to month and year
 *
 * @param	string		field: id of group of fields
 */
function js_jobsBirthdayChange(field) {
	dayField = document.getElementById(field + '_d');
	monthField = document.getElementById(field + '_m');
	yearField = document.getElementById(field + '_y');
	if ((!dayField) || (!monthField) || (!yearField))
		return;
	daySel = dayField.selectedIndex;
	monthSel = monthField.value;
	yearSel = yearField.value;

	jQuery.ajax({
		type: 'GET',
		url: 'index.php',
		data: {eID: 'tx_jobs', cmd: 'birthday_days', year: yearSel , month: monthSel},
		dataType: 'text',
		success: function(result){
			jQuery('#' + field + '_d').html(result);
			dayField.selectedIndex = 0;
			dayLen = dayField.options.length;
			if (dayLen >= (daySel + 1))
				dayField.selectedIndex = daySel;
		}
	});
}