PHP determines if the string encoding is a UTF8 function

Accidentally found such a section of PHP to determine whether the string encoding is UTF8 function, this should be used, save the file, this is said to be perfect judgment function, hope is perfect!

Returns true if $string is valid UTF-8 and False otherwise.  function Is_utf8 ($word)  {      if (Preg_match ("/^ (". Chr (228). ") -". Chr (233)." {1} [". chr (128)." -". Chr (191)." {1} [". chr (128)." -". Chr (191)." {1}) {1}/", $word) = = True | | Preg_match ("/[". chr (228). " -". Chr (233)." {1} [". chr (128)." -". Chr (191)." {1} [". chr (128)." -". Chr (191)." {1}) {1}$/", $word) = = True | | Preg_match ("/[". chr (228). " -". Chr (233)." {1} [". chr (128)." -". Chr (191)." {1} [". chr (128)." -". Chr (191)." {1}) {2,}/", $word) = = True)      {          return true;      }      else      {          return false;      }  }//function Is_utf8

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