public void  removeItemFromEbayList() {
  HttpRequest req = new HttpRequest();
  Http http = new Http();
  sEnvelopHandlerForEndingList='Request XML';
  req.setBody(sEnvelopHandlerForEndingList);
}

{!REQUIRESCRIPT("/soap/ajax/30.0/connection.js")}
{!REQUIRESCRIPT("/soap/ajax/30.0/apex.js")}
//sforce.apex.execute("classname","methodname","parameters seperated by comma");
sforce.apex.execute("classname","removeItemFromEbayList");

webservice void  removeItemFromEbayList(){...}