phpjs/workbench/session/session_encode.js

php.js offers community built php functions in javascript

function session_encode() {
  // http://kevin.vanzonneveld.net
  // +   original by: Louis Stowasser
  // -    depends on: urldecode
  // *     example 1:
  // *     returns 1:

  var _getcookie = function(name) {
    var cookies = document.cookie.split(';'), i = 0, l = cookies.length,
            current;
    for (; i < l; i++) {
      current = cookies[i].split('=');
      //            current[0] = current[0].replace(/\s+/,"");
      if (current[0] === name) {return current[1];}
    }
    return undefined;
  };

  /**
    * Encode string in session format (serialized then url encoded)
    */
  return this.urldecode(_getcookie('JSSESSID'));
}