/******************************************************************************/

function ivFindClass(layer, className) {
  if (!layer.className) layer.className = '';
  var cn = layer.className.split(' ');
  for (var i=0; i<cn.length; i++)
    if (cn[i]==className) return i;
  return -1; 
}
function ivAddClass(layer, className) {
  if (!layer.className) layer.className = '';
  var ix = ivFindClass(layer, className);
  if (ix > -1) return;
  var cn = layer.className.split(' ');
  cn.push(className);
  layer.className = cn.join(' '); 
}
function ivRemoveClass(layer, className) {
  if (!layer.className) layer.className = '';
  var ix = ivFindClass(layer, className);
  if (ix == -1) return;
  var cn = layer.className.split(' ');
  cn.splice(ix, 1);
  layer.className = cn.join(' '); 
}

function ivmo(layer) {
  ivAddClass(layer, 'over');
  if (!layer.onmouseout) layer.onmouseout = function() { ivRemoveClass(this, 'over') };
}

/******************************************************************************/