关闭浏览器时会删除cookie

我有这个cookie来存储用户以前从菜单中选择的内容。但我希望即使用户关闭浏览器，也要将此cookie保存在浏览器中。此代码完全适用于IE，但当我关闭Chrome和Firefox时，cookie被删除。任何人都可以为我提供解决方案。

I have this cookie to store users previous selection from a menu. But I want keep this cookie stored in the browser even if the user closes the browser. This code perfectly works on IE but when I close Chrome and Firefox, the cookie getting deleted. Can anyone provide me solution for this.

function setCookie(NameOfCookie, value, expiredays) {
    var ExpireDate = new Date();
    document.cookie = NameOfCookie + "=" + escape(value) + ((expiredays == null) ? "" : "; expires=" + ExpireDate.toGMTString());
}

function delCookie (NameOfCookie) {
  if (getCookie(NameOfCookie)) {
    document.cookie = NameOfCookie + "=" + "; expires=Thu, 17-Jul-24 00:00:01 GMT";
  }
}