$(document).ready(function() {
	var minYear = findMinYear();
	var maxYear = findMaxYear();

	$('#begYear').prepend('<option value="0">All Years</option>');
	$('#begYear').append('<option value="0">All Years</option>');
	$('#endYear').prepend('<option value="0">All Years</option>');
	$('#endYear').append('<option value="0">All Years</option>');

	$("#begYear").change(function(){ begYearChange(minYear,maxYear) });
	$("#endYear").change(function(){ endYearChange(minYear,maxYear) });
});

function findMinYear() {
    var minYear = undefined;
    var val     = undefined;
    $('option', $('#begYear')).each(function() {
        val = parseInt($(this).attr('value'), 10);
        if (minYear === undefined || minYear > val) minYear = val;
    });
    return minYear;
}

function findMaxYear() {
    var maxYear = undefined;
    var val     = undefined;
    $('option', $('#begYear')).each(function() {
        val = parseInt($(this).attr('value'), 10);
        if (maxYear === undefined || maxYear < val) maxYear = val;
    });
    return maxYear;
}

function begYearChange(minYear,maxYear){
	if (parseInt($('#begYear').val()) < 1) {
		$('#begYear').val(minYear);
		$('#endYear').val(maxYear);
	} else if ($('#begYear').val() > $('#endYear').val()) {
		$('#endYear').val($('#begYear').val());
	}
}

function endYearChange(minYear,maxYear){
	if (parseInt($('#endYear').val()) < 1) {
		$('#begYear').val(minYear);
		$('#endYear').val(maxYear);
	} else if ($('#endYear').val() < $('#begYear').val()) {
		$('#begYear').val($('#endYear').val());
	}
}