Note: After saving, you have to bypass your browser's cache to see the changes. Google Chrome, Firefox, Microsoft Edge and Safari: Hold down the ⇧ Shift key and click the Reload toolbar button. For details and instructions about other browsers, see Wikipedia:Bypass your cache.
// install [[User:Cacycle/diff]] text diff code
document.write('<script type="text/javascript" src="' 
  + 'http://en.wikipedia.org/w/index.php?title=User:Cacycle/diff.js' 
  + '&action=raw&ctype=text/javascript&dontcountme=s"></script>');

// install [[User:Pilaf/Live_Preview]] page preview tool
document.write('<script type="text/javascript" src="' 
  + 'http://en.wikipedia.org/w/index.php?title=User:Pilaf/livepreview.js' 
  + '&action=raw&ctype=text/javascript&dontcountme=s"></script>');

// install [[User:Cacycle/editor]] edit tool
document.write('<script type="text/javascript" src="' 
  + 'http://en.wikipedia.org/w/index.php?title=User:Cacycle/editor.js' 
  + '&action=raw&ctype=text/javascript&dontcountme=s"></script>');




function addStrikeoutButton() {

    editingTools = document.getElementById('toolbar');

    if (editingTools != null)  {

        StrikeTextButton = "  <a href=\"javascript:insertTags('<s>','</s>','Insert text here');\"><img src=\"http://upload.wikimedia.org/wikipedia/en/c/c9/Button_strike.png\" alt=\"Strike\" title=\"Strike-through text\"></a>";
 
        editingTools.innerHTML = editingTools.innerHTML + StrikeTextButton;
    }
}

window.onload = addStrikeoutButton;