php 区分中文，英文，中英混合

            $str1="是你";
            $strA = trim($str1);
            $lenA = strlen($strA);
            $lenB = mb_strlen($strA,"utf-8");
            if($lenA===$lenB){
                echo "英文";
            }else{
                if($lenA % $lenB == 0){
                    echo "中文"; 
                  }else{
                    echo  "中英";
                  }
            }