
 
        Gets the child element index closest to the given offset.
 The offset is specified relative to the beginning of the
 document.  Returns 
-1 if the 
Element is a leaf, otherwise returns
 the index of the 
Element that best represents
 the given location.  Returns 
0 if the location
 is less than the start offset. Returns 
getElementCount() - 1 if the location is
 greater than or equal to the end offset.
        
        
Returns:
    the element index >= 0 
Parameters:
 - 
offset - the specified offset >= 0