Required library edition:
Required library file: dhtmlxaccordion.js

enables multimode in accordion (disabled by the default)

var dhxAcc = new dhtmlXAccordion(...);
  // first enabling multimode
dhxAcc.enableMultiMode(true);
  // then adding items
dhxAcc.adItem("item_a", "The Secret of Monkey Island");
dhxAcc.adItem("item_b", "Monkey Island 2: LeChuck's Revenge");
dhxAcc.adItem("item_c", "The Curse of Monkey Island");
  ...