~ questions about displaying custom length strings

Asking questions about displaying custom length strings
I wrote a custom string length function, the code is as follows:

PHP code

  
  function _word_num ($string, $length) {        $string = trim ($string);        if (strlen ($string) > $length) {            return (mb_substr ($string, 0, $length, "GBK"). " ...");        } else {            return $string;        }    }

The problem is ... After using this function, regardless of the length of the match, all added "...", to explain:

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Code I also think no problem, maybe I think is the string is Chinese, but the landlord needs to know the Chinese strlen is twice times the English, then determine the length of time need to pay attention to.
If the landlord would have known, then I do not know why
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The code is really fine ...
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Give your test data.

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