chunk_split 将字符串分割成小块

[TOC] ## 实例 ``` $email = 'name@example.com'; echo chunk_split($email,5,',');// end 默认 行尾序列符号 //name@,examp,le.co,m, $email = '你好啊世界!abcdefg'; echo chunk_split($email,6,','); //你好,啊世,界!ab,cdefg, ```