Google Earth For Javascript 谷歌地球删除所有标记

//前提是google earth 已经在页面加载   即 ge!= null 否则报错

function removeAllMarker()
{
 var allChildren = ge.getFeatures().getChildNodes();
 for(i=0;i<allChildren.getLength();i++)
 {
  if(allChildren.item(i).getType() == 'KmlPlacemark')
  { 

    ge.getFeatures().removeChild(allChildren.item(i));
  }
 }
}