单击任何输入框后关闭下拉菜单

我创建了一个下拉菜单，在其中我创建了搜索条件的表单。现在，每当我点击任何输入框，菜单就会关闭。有什么办法解决吗？

这是我的html代码：

<ul class="nav navbar-nav">
<li class="dropdown dropdown-large">
    <a href="#" class="dropdown-toggle" data-toggle="dropdown">Search<b class="caret"></b></a>

    <ul class="dropdown-menu dropdown-menu-large row">
        <center>Search Criteria</center>
        <hr>
        <li class="col-sm-3">
            <ul>
                <li>Profile ID</li>
                <li>
                    <input type="text">
                </li>
            </ul>
        </li>
        <li class="col-sm-3">
            <ul>
                <li>Name</li>
                <li>
                    <input type="text">
                </li>
            </ul>
        </li>
        <li class="col-sm-3">
            <ul>
                <li>Age</li>
                <li>
                    <input type="text" size="5">&nbsp;to&nbsp;
                    <input type="text" size="5">
                </li>
            </ul>
        </li>
        <li class="col-sm-3">
            <ul>
                <li>Date of Birth</li>
                <li>
                    <input type="date">
                </li>
            </ul>
        </li>
    </ul>
</li>

和我的css代码：

    .dropdown-large {
  position: static !important;
}
.dropdown-menu-large {
  margin-left: 16px;
  margin-right: 16px;
  padding: 20px 0px;
}
.dropdown-menu-large > li > ul {
  padding: 0;
  margin: 0;
}
.dropdown-menu-large > li > ul > li {
  list-style: none;
}
.dropdown-menu-large > li > ul > li > a {
  display: block;
  padding: 3px 20px;
  clear: both;
  font-weight: normal;
  line-height: 1.428571429;
  color: #333333;
  white-space: normal;
}
.dropdown-menu-large > li ul > li > a:hover,
.dropdown-menu-large > li ul > li > a:focus {
  text-decoration: none;
  color: #262626;
  background-color: #f5f5f5;
}
.dropdown-menu-large .disabled > a,
.dropdown-menu-large .disabled > a:hover,
.dropdown-menu-large .disabled > a:focus {
  color: #999999;
}
.dropdown-menu-large .disabled > a:hover,
.dropdown-menu-large .disabled > a:focus {
  text-decoration: none;
  background-color: transparent;
  background-image: none;
  filter: progid:DXImageTransform.Microsoft.gradient(enabled = false);
  cursor: not-allowed;
}
.dropdown-menu-large .dropdown-header {
  color: #428bca;
  font-size: 18px;
}
@media (max-width: 768px) {
  .dropdown-menu-large {
    margin-left: 0 ;
    margin-right: 0 ;
  }
  .dropdown-menu-large > li {
    margin-bottom: 30px;
  }
  .dropdown-menu-large > li:last-child {
    margin-bottom: 0;
  }
  .dropdown-menu-large .dropdown-header {
    padding: 3px 15px !important;
  }
}