function getCurrMapExtent(){

 var objMapFrm = parent.map.document.MapFrm

 var xmin = objMapFrm.currEx1.value
 var ymin = objMapFrm.currEy1.value
 var xmax = objMapFrm.currEx2.value
 var ymax = objMapFrm.currEy2.value

  var str = "x1=" + xmin + "&x2=" + xmax + "&y1=" + ymin + "&y2=" + ymax

  return str
}