(PHP 5, PHP 7, PHP 8)
DOMCharacterData::insertData — Insert a string at the specified 16-bit unit offset
$offset, string $data): bool
   Inserts string data at position offset.
  
offsetThe character offset at which to insert.
dataThe string to insert.
没有返回值。
DOM_INDEX_SIZE_ERR
       Raised if offset is negative or greater than the
       number of 16-bit units in data.