document.cookie = 'name=value1; path=/';
document.cookie = 'name=value2; path=/path/';

alert(document.cookie); // name=value1; name=value2


document.cookie = 'name=; path=/path/; expires=' + new Date(0).toUTCString();

alert(document.cookie); // name=value1

将其更改为以/的路径过期的cookie仍然只会过期其中一个cookie – 给定的路径必须匹配路径集：

document.cookie = 'name=; path=/; expires=' + new Date(0).toUTCString();

alert(document.cookie); // name=value2

要删除这两个,您必须使用他们的路径到期：

document.cookie = 'name=; path=/; expires=' + new Date(0).toUTCString();
document.cookie = 'name=; path=/path/; expires=' + new Date(0).toUTCString();

alert(document.cookie); // {blank}

现在,这些例子假设你正在浏览/ path /或者一个子目录.

[编辑]

要大量删除,请尝试这样：

function expireAllCookies(name,paths) {
    var expires = new Date(0).toUTCString();

    // expire null-path cookies as well
    document.cookie = name + '=; expires=' + expires;

    for (var i = 0,l = paths.length; i < l; i++) {
        document.cookie = name + '=; path=' + paths[i] + '; expires=' + expires;
    }
}

expireAllCookies('name',['/','/path/']);

演示：http://jsfiddle.net/M2dZ3/

您还可以通过拆分和迭代window.location.pathname来伪造路径查找：

function expireActiveCookies(name) {
    var pathname = location.pathname.replace(/\/$/,''),segments = pathname.split('/'),paths = [];

    for (var i = 0,l = segments.length,path; i < l; i++) {
        path = segments.slice(0,i + 1).join('/');

        paths.push(path);       // as file
        paths.push(path + '/'); // as directory
    }

    expireAllCookies(name,paths);
}

演示：http://jsfiddle.net/M2dZ3/2/