javascript turn single line break to double line break
<p>Hm... I'm trying to convert single line break into double line break, as in</p>

<blockquote>
  <p>This is a sentence.<br>
  This is another sentence.</p>
</blockquote>

<p>into</p>

<blockquote>
  <p>This is a sentence.</p>
  
  <p>This is another sentence.</p>
</blockquote>

<p>Apparently this doesn't work <code>ThisContent = ThisContent.replace(/(\n)/gm, "\n\n");</code> since it replace everything, including double line breaks.</p>

<p>What's the regex to do this?</p>
