Ask the user for a ID Name and show the value.

HOW TO USE:
1 - Load a site.
2 - Perform action.
3 - Load the Bookmarklet.
4 - Type ID name.
5 - The script will return the value.

javascript:alert(document.getElementById(prompt("Type id name:", "")).value);

Save the code on your browser favorites and use after the page have been loaded.