我使用引导面板，并添加了一个跨度可点击图标：当面板主体打开时加号，当面板主体关闭时减号，我现在的问题是我如何才能将其设置为默认关闭（默认情况下以及我显示的加号图标）单击它，面板主体将打开）
以上是我执行此操作的代码，在此先感谢您的帮助。
<html>
<head>
<!-- Latest compiled and minified CSS -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">
<!-- Optional theme -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap-theme.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
<!-- Latest compiled and minified JavaScript -->
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
<script>
$(document).on('click', '.panel-heading span.clickable', function (e) {
var $this = $(this);
if (!$this.hasClass('panel-collapsed')) {
$this.parents('.panel').find('.panel-body').slideUp();
$this.addClass('panel-collapsed');
$this.find('i').removeClass('glyphicon-minus').addClass('glyphicon-plus');
} else {
console.log($this);
$this.parents('.panel').find('.panel-body').slideDown();
$this.removeClass('panel-collapsed');
$this.find('i').removeClass('glyphicon-plus').addClass('glyphicon-minus');
}
});
</script>
<style>
.clickable
{
cursor: pointer;
}
.clickable .glyphicon
{
background: rgba(0, 0, 0, 0.15);
display: inline-block;
padding: 6px 12px;
border-radius: 4px …