substr and UTF-8

Hi group, I want to limit the number of characters that are shown in a script. The characters happen to be Thai, and the page is encoded in UTF-8. Everything works, except when I want to cut the text (just take start of string). I do: echo substr($thaistring, 0, 30); The beginning of the string works fine, but the last character does mostly "break". How can I determine the start and end of a character. I hope the problem is clear enough, is it? :) Best regards, Peter Lauri www.lauri.se - personal web site www.dwsasia.com - company web site