Searching in Elements and copying certain text

Good Day,

Is there any script or anyone can make a script for copying certain text in the elements for all tabs??

Example: Searching for "" and copying his username before

johnsmith

Copying the johnsmith.

Example: Searching for "<span id="username">" and copying his username before </span>

You can easily find the tag's text content in a tab:

var user = document.getElementById("username").textContent;

But... I'm not sure what you have in mind for reading across all tabs and what should go on the clipboard when (if you mean copying to the clipboard).