js 设置cookie 读取cookie 删除cookie

//设置cookie

  setCookie: function(cname, cvalue, exdays) {

    var d = new Date();

    d.setTime(d.getTime() + (exdays * 60 * 60 * 1000));

    var expires = "expires=" + d.toUTCString();

    document.cookie = cname + "=" + cvalue + "; " + expires;

  },

  //获取cookie

  getCookie: function(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) != -1) return c.substring(name.length, c.length);

    }

    return "";

  },

  //清除cookie

  clearCookie: function(name) {

    this.setCookie(name, "", -1);

  },

把这些单独放入一个js文件， 然后引用，  然后就可以用了。