User:Plingle/monobook.js

// This script changes the "Your signature with timestamp" edit button to use a real em dash instead of two hyphens. (function {    var oldAddButton = window.addButton;    if (typeof(oldAddButton) != 'function') return;    window.addButton = function  {        if (arguments.length > 2)            arguments[2] = arguments[2].replace(/^--(~+)$/, '—$1');        oldAddButton.apply(this, arguments);    }; });