问如何在输入引导日期选择器中仅显示年份？

EN

$("#datepicker").datepicker({
    format: "yyyy",
    viewMode: "years", 
    minViewMode: "years"
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-datepicker/1.6.4/js/bootstrap-datepicker.js"></script>
<link href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-datepicker/1.6.4/css/bootstrap-datepicker.css" rel="stylesheet"/>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"/>


<input type="text" id="datepicker" />

$("#datepicker").datepicker( {
    format: " yyyy", // Notice the Extra space at the beginning
    viewMode: "years", 
    minViewMode: "years"
});

$(".years").datetimepicker({
    format: "yyyy",
    startView: 'decade',
    minView: 'decade',
    viewSelect: 'decade',
    autoclose: true,
});

$("#year").datepicker( {
    format: "yyyy",
    viewMode: "years", 
    minViewMode: "years"
}).on('changeDate', function(e){
    $(this).datepicker('hide');
});