title: adding rel="nofollow" while saving data
body: <p>I have my application to allow users to write comments on my website. Its working fine. I also have tool to insert their weblinks in it. I feel good with contents with their own weblinks.</p>
  
  <p>Now i want to add rel="nofollow" to every links on content that they have been written.</p>
  
  <p>I would like to add rel="nofollow" using php i.e while saving data. </p>
  
  <p>So what's a simple method to add rel="nofollow" or updated rel="someother" with rel="someother nofollow" using php</p>
  
  <p>a nice example will be much efficient</p>