perform dialog


          function dialog(){
                  var Input = document.Eliza.input.value;          // capture input and copy to log
                  document.Eliza.input.value = "";        
                  chatter[chatpoint] = " \n* " + Input;
                  elizaresponse = listen(Input);
                  setTimeout("think()", 1000 + Math.random()*3000);
                  chatpoint ++ ; 
                  if( chatpoint >= chatmax ){ chatpoint = 0; }
                  return write();
          }