DOMCharacterData->substringData()
DOMCharacterData->substringData() -- 
   Extracts a range of data from the node
  
Description
class 
DOMCharacterData { 
string 
substringData ( int offset, int count )
}
   Returns the specified substring. 
  
Parameters
   
- offset
- 
       Start offset of substring to extract.
       
- count
- 
       The number of characters to extract.
       
Return Values
   The specified substring. If the sum of offset 
   and count exceeds the length, then all 16-bit units 
   to the end of the data are returned.
  
Exceptions
   
- DOM_INDEX_SIZE_ERR
- 
       Raised if offset is negative or greater than the
       number of 16-bit units in data, or if count is 
       negative.