HTML contenteditable Attribute

The contenteditable attribute, when set to true, makes the content of an element editable (hence the name).

Syntax: contenteditable="Boolean value"

Here's a code snippet:

        <div style="border: 2px solid #000000; width: 250px; height: 250px; padding: 5px;" contenteditable="true">
  <p>I can be edited!!!</p>
  <p>In Chrome, you can press (on the keyboard) Ctrl + B for <b>bold</b>, Ctrl + I for <i>italic</i>, and Ctrl + U for <u>underline</u>.</p>
  <button>My content can be edited too (if not working, try double-clicking)!!!</button>
</div>
      

When run, this will be the result (click inside the <div> and change stuff).

To edit other webpages (temporarily, current session only), drag the hilarious "Edit Webpage" and "Save Webpage Edits" bookmarklets (located here) to your bookmarks bar.