var speed = 8;
var itv = 0;
var scv = 0;
var scs = 20;

function scrollnow() {
  var cn = document.getElementById( 'bs_container' );
  var sa = document.getElementById( 'bs_area' );
  // Get offset
  var cl = sa.offsetLeft;
  // Move area
  var nl = cl + scv;
  // Boundary check
  if( nl < minw ) {
    nl = minw;
  }
  if( nl > 0 ) {
    nl = 0;
  }
  // Set new location
  sa.style.left = nl + 'px';
}

function sl() {
  scv = speed;
  itv = setInterval( 'scrollnow()', 50 );
}
function sr() {
  scv = -1 * speed;
  itv = setInterval( 'scrollnow()', 50 );
}
function ss() {
  clearInterval( itv );
  itv = 0;
}
function su() {
  scv = scv * 2;
}
function sd() {
  scv = scv / 2;
}