var testStr = "hello kay!";

1、substr

  testStr.substr(1)   ->ello kay!  

  testStr.substr(1,4) ->ello (4是长度)

2、substring

  

  testStr.substring(1)   ->ello kay!  

  testStr.substr(1,4) ->ello(4是第4个字符)

04-26 05:00