gistfile1.js

// ==UserScript==
// @name           Disable Ctrl+s and Ctrl+t interceptions
// @description    Stop websites from highjacking keyboard shortcuts
//
// @run-at         document-start
// @include        *
// @grant          none
// ==/UserScript==

// This was taken from here: http://superuser.com/a/670040/307969 and modified slightly.

keycodes = [9, 83, 84];  

(window.opera ? document.body : document).addEventListener('keydown', function(e) {
    if (keycodes.indexOf(e.keyCode) != -1 && e.ctrlKey) {
        e.cancelBubble = true;
        e.stopImmediatePropagation();
    }
    return false;
}, !window.opera);