Extract and Replace Links in HTML with JavaScript RegEx

For the Mail Merge project, I need to extract all the hyperlinks in the email message and append email tracking parameters to each of the links. The links can be either embedded in the HTML <a> tag or they can be mentioned in plain text like example.com – Gmail and other email clients are smart enough to replace such plain text website links into clickable hyperlinks.

I’m using RegEx to pull out these links from HTML / Text and then a simple JavaScript function to manipulate the link.

Replace Links inside HTML Tags

Convert Plain Text into Links

Some text make contain links in plain text and this method would replace such links into clickable hyperlinks by adding the anchor tag.