Replace Placeholder and Echo Content
<p>I have the content variable <code>$number['content']</code> with the placeholder <code>&lt;!--email--&gt;</code>  in it which needs to be replaced with <code>$email</code> variable. </p>

<p>Below is whats being stored in the content variable.
<code>&lt;iframe src="url.com&amp;em=&lt;!--email--&gt;&amp;se=51" style="width:900px;height:700px;"&gt;&lt;/iframe&gt;</code></p>

<p>I need  to be replaced with the variable <code>$email</code> </p>
