Javascript:How to get content of a url?
<pre>As we know, we can use the function `file_get_contents(url)` in PHP to get content of a url.</pre>

<p>However, can it be avaible in JavaScript? </p>

<pre>The `document.ElementById()` is only valid in current page.</pre>

<p>Can I use JS to get a <code>div</code> or <code>class</code> in an URL?</p>

<p>Moreover, if these content can be displayed through <code>PopupBubble</code>, I will be more grateful to you.</p>
