// JavaScript Document
function walkKmlDom(rootObject, visitCallback, options) {
  options = options || {};
  
  if (!('features' in options)) {
    options.features = true;
  }
  
  if (!('geometries' in options)) {
    options.geometries = false;
  }
  
  var recurse_ = function(object, currentContext) {
    var contextArgument = {
      current: currentContext,
      child: currentContext,
      walkChildren: true
    };
    
    // walk object
    var retValue = visitCallback.call(object, contextArgument);
    if (!retValue && typeof retValue !== 'undefined') {
      return false;
    }
    
    if (!contextArgument.walkChildren) {
      return true;
    }
    
    var objectContainer = null; // GESchemaObjectContainer
    
    // check if object is a parent
    if ('getFeatures' in object) { // GEFeatureContainer
      if (options.features) {
        objectContainer = object.getFeatures();
      }
    } else if ('getGeometry' in object) { // KmlFeature - descend into geoms.
      if (options.geometries && object.getGeometry()) {
        recurse_(object.getGeometry(), contextArgument.child);
      }
    } else if ('getGeometries' in object) { // GEGeometryContainer
      if (options.geometries) {
        objectContainer = object.getGeometries();
      }
    } else if ('getInnerBoundaries' in object) { // GELinearRingContainer
      if (options.geometries) {
        objectContainer = object.getInnerBoundaries();
      }
    }
    
    // iterate through children if object is a parent and recurse so they
    // can be walked
    if (objectContainer && objectContainer.hasChildNodes()) {
      var childNodes = objectContainer.getChildNodes();
      var numChildNodes = childNodes.getLength();
      
      for (var i = 0; i < numChildNodes; i++) {
        var child = childNodes.item(i);
        
        if (!recurse_(child, contextArgument.child))
          return false;
      }
    }
    
    return true;
  };
  
  recurse_(rootObject, options.rootContext);
};