设置cookie,和过期时间，同域请求

function setCookie(key, value, iDay) {
    var cookieArr = document.cookie.split('; ');
    for(var i = 0; i < cookieArr.length; i++) {
        var arr = cookieArr[i].split('=');
        if(arr[i] === key) {
            return false;
        }else{
            var oDate = new Date();
            oDate.setDate(oDate.getDate() + iDay);
            document.cookie = key + '=' + value + ';expires=' + oDate+"; path=/";
        }
    } return false;


}