title: Replace anchor tag value with anchor title if href value is empty by regex
body: <p>I am trying to replace the anchor tag value with anchor's title value if any anchor tag's href attribute is blank. </p>
  
  <p>Like </p>
  
  <pre><code>&lt;a xlink:href=""&gt;Lorem Ipsum&lt;/a&gt;  is simply dummy text of the printing and typesetting industry&lt;a xlink:href ="http://google.com"&gt;Google&lt;/a&gt;. 
  </code></pre>
  
  <p>if I try with below regex:</p>
  
  <pre><code>&lt;a [^&gt;]+&gt;(.*?)&lt;\/a&gt;
  </code></pre>
  
  <p>DEMO <a href="http://regexr.com/3h6on" rel="nofollow noreferrer">http://regexr.com/3h6on</a></p>
  
  <p>then output I am getting below </p>
  
  <pre><code>Lorem Ipsum is simply dummy text of the printing and typesetting industry Google. 
  </code></pre>
  
  <p>it replaced both anchor tag with Anchor Text value, and I need to replace those anchor tag where the href attribute value is empty. </p>
  
  <p>I need an output like below </p>
  
  <pre><code>Lorem Ipsum is simply dummy text of the printing and typesetting industry&lt;a xlink:href ="http://google.com"&gt;Google&lt;/a&gt; 
  </code></pre>