Replacing "HTML tag with content" with "content"
<p>I need to replace</p>

<pre><code>&lt;span class='foo'&gt;bar&lt;/span&gt; 
</code></pre>

<p>with</p>

<pre><code>bar
</code></pre>

<p>using JavaScript / jQuery.</p>

<p>Note: tag content must be inserted exactly in the same place, where tag was.</p>
