How to make link attribute to nofollow in all links

PHP
1

How to make link attribute to nofollow in all links?

I have some lines of text, which also contains links and images. But i want to know any way so that without changing the text from inside, I could make all links with rel=nofollow.

using either preg_replace or something else.

But I don’t know the way to start with.
Can someone guide me?

2

You have two options there.

  1. Use regular expressions to process the HTML code
  2. Convert the text to an XML structure, then process from there

In this case, I might be tempted to go with the second option.