Js获取Cookie值的方法

function getCookie(name) {
    var prefix = name + "="
    var start = document.cookie.indexOf(prefix)
 
    if (start == -1) {
        return null;
    }
 
    var end = document.cookie.indexOf(";", start + prefix.length)
    if (end == -1) {
        end = document.cookie.length;
    }
 
    var value = document.cookie.substring(start + prefix.length, end)
    return unescape(value);
}