从http://www.quirksmode.org/js/cookies.html#script被盗

function createCookie(name,value,days) {
    if (days) {
        var date = new Date();
        date.setTime(date.getTime()+(days*24*60*60*1000));
        var expires = "; expires="+date.toUTCString();
    }
    else var expires = "";
    document.cookie = name+"="+value+expires+"; path=/";
}

function readCookie(name) {
    var nameEQ = name + "=";
    var ca = document.cookie.split(';');
    for(var i=0;i < ca.length;i++) {
        var c = ca[i];
        while (c.charAt(0)==' ') c = c.substring(1,c.length);
        if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
    }
    return null;
}

function eraseCookie(name) {
    createCookie(name,"",-1);
}

使用它：

var oldCount = parseInt(readCookie('hitCount'), 10) || 0;
createCookie('hitCount', oldCount + 1, 7);

如评论中指出的那样，由于cookie被存储并作为字符串返回，因此您应该将其强制转换为int。使用foo++或++foo会为您实际投放，但更确切地知道您正在使用的是更安全的方法：

var x = "5";  // x = "5" (string)
x += 1;       // x = "51" (string!)
x += 5;       // x = "515" (string!)
++x;          // x = 516 (number)