[detaro]

Could use Javascript to search-replace the text. Progressive enhancement and all :D

[saagarjha]

I stubbornly refuse to serve JavaScript on my website, but perhaps I can whip up a snippet that you can self-XSS yourself with.

[5-]

How's this?

  document.body.innerHTML=document.body.innerHTML.replace(/\$[\w_]*/g,'<span contenteditable role="$&" style="border:dashed 1px gray">$&</span>');document.querySelectorAll('span[role]').forEach(s=>s.addEventListener('input',e=>document.querySelectorAll('span[role="'+e.target.getAttribute('role')+'"]').forEach(t=>t!=e.target&&(t.textContent=e.target.textContent))))