[javascript] Cookie Read and Write

cookie_read_write.js

function createCookie(name, value, days) {
      if (days) {
          var date = new Date();
          date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
          var expires = "; expires=" + date.toGMTString();
      }
      else var expires = "";               

      document.cookie = name + "=" + value + expires + "; path=/";
  }

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

  function eraseCookie(name) {
      createCookie(name, "", -1);
  }