title: put a <br /> tag after some text
body: <p>I have a variable str which is having some text. I just show this text on the my UI.
         But I have a condition, suppose this variable is having 5oo words, so I need to put a <br /> tag after every 50 words.</p>
  
  <p>How can I do that?</p>
  
  <p>below is my c# code through which I am sending a mail as html</p>
  
  <pre><code>Emailbody += " &lt;tr&gt;";
  Emailbody += " &lt;td align='left' valign='Top' nowrap&gt;&lt;span class=style17&gt;Purpose of     travel&lt;/span&gt;&lt;/td&gt;";
  Emailbody += "&lt;td align='center' valign='Top'&gt;:&lt;/td&gt;";
  Emailbody += " &lt;td align='left' valign='Top'&gt;&lt;span class=style17&gt;&amp;nbsp;&amp;nbsp;" + TextBox1.Text +     "&lt;/span&gt;&lt;/td&gt;";
  Emailbody += " &lt;td&gt;&amp;nbsp;&lt;/td&gt;";
  Emailbody += "  &lt;td align='left' nowrap'&gt;&lt;span class=style17&gt;Advance&lt;/span&gt;&lt;/td&gt;";
  Emailbody += " &lt;td align='center'&gt;:&lt;/td&gt;";
  Emailbody += "&lt;td align='left' nowrap&gt;&lt;span class=style17&gt;"+TextBox2.Text+"&lt;/td&gt;";
  Emailbody += " &lt;/tr&gt;";
  </code></pre>
  
  <p>I need the the solution for mt TextBox1.Text</p>