javascript - substr和substring有什么区别？(What is the difference between substr and substring?)

Question

What is the difference between

(之间有什么区别)

alert("abc".substr(0,2));

and

(和)

alert("abc".substring(0,2));

They both seem to output “ab”.

(他们似乎都输出“ ab”。)

  ask by Difference Engine translate from so

Answer 1

The difference is in the second argument.

(区别在于第二个参数。)

The second argument to substring is the index to stop at (but not include), but the second argument to substr is the maximum length to return.

(substring的第二个参数是要在（但不包括）处停止的索引，而substr的第二个参数是要返回的最大长度。)

Links?

(链接？)

https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/String/substr

(https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/String/substr)

https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/String/substring

(https://developer.mozilla.org/zh-CN/JavaScript/Reference/Global_Objects/String/substring)