mb_detect_encoding($firstStr, array("ASCII","UTF-8","GB2312","GBK","BIG5")); #判断字符编码
mb_substr #获取字符长度
preg_match("/[\x7f-\xff]/",$firstStr) # 判断中文
preg_match("/[a-zA-Z]/", $firstStr) # 判断英文

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