function calculateAnuita( years, interest, mortgage ) {
	var paymentNumber = 12 * years;
	var power = Math.pow( 1 + ( interest / 12 ), paymentNumber );
	var anuita = ( mortgage * ( interest / 12 ) * power / ( power - 1) );
	
	return Math.round( anuita );
}

function recalculateHypo() {
	var form = $(".finance .form").get[0];

	var mortgage = $(form).find( "input[name='vyska']" ).val();
	var interest = $(form).find( "input[name='sadzba']" ).val();
	
	mortgage = mortgage.replace( ',', '.' ) * 1;
	interest = interest.replace( ',', '.' ) / 100;

	if( isNaN(mortgage) ||  isNaN( interest ) ) {
		alert( msg_not_a_number );
		return;
	}

	var years = $(form).find( "select option:selected" ).val();

	if( mortgage != 0 && interest != 0 && years != 0 ) {
		var splatky = calculateAnuita( years, interest, mortgage );
		$(form).find( "input[name='splatky']").val( splatky + ",- Kč" );
	}
}

function initHypo() {
	$(document).ready( function () {
		$(".finance .form input[id]").change( recalculateHypo );
		$(".finance .form select").change( recalculateHypo );
	} );
}