Returns a string representing the content at the given range.
<p>
@param start the start offset of the text to return. Offset 0 is the
first character of the document.
@param length the length of the text to return
@return the text at the given range
Returns a string representing the content at the given range. <p>
@param start the start offset of the text to return. Offset 0 is the first character of the document. @param length the length of the text to return @return the text at the given range