曾经跳过的坑----js截取字符串substr与substring 和 trim
不废话直接代码。自己理解。。。。。。
> "abcdefg".substring(1,6)
> "bcdef"
> "abcdefg".substr(1,6)
> "bcdefg"
> "abcdefg".substr(0,6)
> "abcdef"
> "abcdefg".substring(0,6)
> "abcdef"
> " aaaaa ".trim()
> "aaaaa"
> $.trim(" aaa")
> "aaa"