您可以使用所需cookie的名称调用函数getcookie，然后检查其是否为null。
function getcookie(name) { var dc = document.cookie; var prefix = name + "="; var begin = dc.indexOf("; " + prefix); if (begin == -1) { begin = dc.indexOf(prefix); if (begin != 0) return null; } else { begin += 2; var end = document.cookie.indexOf(";", begin); if (end == -1) { end = dc.length; } } // because unescape has been deprecated, replaced with depreURI //return unescape(dc.substring(begin + prefix.length, end)); return depreURI(dc.substring(begin + prefix.length, end));}function doSomething() { var mycookie = getcookie("Mycookie"); if (mycookie == null) { // do cookie doesn't exist stuff; } else { // do cookie exists stuff }}
