JS - Cookie: getCookie, setCookie

JS function for Cookie

如果cookie未设置，判断时与空字符串‘’比较；

function setCookie(cname, cvalue, exdays) {
    var d = new Date();
    d.setTime(d.getTime() + (exdays*24*60*60*1000));
    var expires = "expires="+d.toUTCString();
    document.cookie = cname + "=" + cvalue + "; " + expires;
}

function getCookie(cname) {
    var name = cname + "=";
    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);
        if (c.indexOf(name) == 0) return c.substring(name.length,c.length);
    }
    return "";
 }

当使用jQuery cookie时，

$.cookie('the_cookie'); // 读取 cookie
$.cookie('the_cookie', 'the_value'); // 存储 cookie
$.cookie('the_cookie', 'the_value', { expires: 7 }); // 存储一个带7天期限的 cookie
$.cookie('the_cookie', '', { expires: -1 }); // 删除 cookie

如果cookie未设置，判断时与undefined比较；