string effect

Hi, since a long time now, i see that some paragraphs of text are cut off and the additional text is replaced by 3 dots. e.g: "this is the original long text but without any sense and also stupid" effect desired : "this is the original long text..." this is usually used for title articles or some long paragraphs. What is the basic rule ? Text is cut off based on (numbers of words, number of characters,..) ? what is the algorithm for such thing ? thanks a lot, -- Alain ------------------------------------ Windows XP SP2 PostgreSQL 8.2.4 / MS SQL server 2005 Apache 2.2.4 PHP 5.2.4 C# 2005-2008