读饼干
var name = name + "=",
cookie_array = document.cookie.split(';'),
cookie_value;
for(var i=0;i<cookie_array.length;i++) {
var cookie=cookie_array[i];
while(cookie.charAt(0)==' ')
cookie = cookie.substring(1,cookie.length);
if(cookie.indexOf(name)==0)
cookie_value = cookie.substring(name.length,cookie.length);
}
这会将 cookie_value
设置为 cookie 的值(如果存在)。如果没有设置 cookie,它会将 cookie_value
设置为 null