jQuery选择自定义属性为指定内容的元素

在日常开发中，我们经常会用到自定义属性，那么jQuery如何选择自定义属性为指定内容的元素呢？

示例HTML代码：

	<ul>
	    <li class="dd-item" data-nav-url="/a/getting-started/installation.html">
	        <a href="/a/getting-started/installation.html">
	            <i class="fa fa-check read-icon"></i>
	            <span><b></b>安装</span>
	        </a>
	    </li>
	    <li class="dd-item" data-nav-url="/a/getting-started/basic-usage.html">
	        <a href="/a/getting-started/basic-usage.html">
	            <i class="fa fa-check read-icon"></i>
	            <span><b></b>基本用法</span>
	        </a>
	    </li>
	    <li class="dd-item" data-nav-url="/a/getting-started/builds-and-modules.html">
	        <a href="/a/getting-started/builds-and-modules.html">
	            <i class="fa fa-check read-icon"></i>
	            <span><b></b>版本和模块</span>
	        </a>
	    </li>
	</ul>

如果我们想获取data-nav-url值为/a/getting-started/basic-usage.html的li，jQuery代码如下：

	var l = jQuery("li[data-nav-id='/a/getting-started/basic-usage.html']");