How to convert a String to long in javascript?

问题:

I have a millisecond timestamp that I need to convert from a String to long. Javascript has a parseInt but not a parseLong. So how can I do this?

Thanks

Edit: To expand on my question slightly: given that apparently javascript doesn't have a long type, how can I do simple arithmetic with longs that are initially expressed as strings? E.g subtract one from the other to get a time delta?

回答1:

JavaScript has a Number type which is a 64 bit floating point number*.

If you're looking to convert a string to a number, use

1. either parseInt or parseFloat. If using parseInt, I'd recommend always passing the radix too.
2. use the Unary + operator e.g. +"123456"
3. use the Number constructor e.g. var n = Number("12343")

*there are situations where the number will internally be held as an integer.

回答2:

It's because there is no long in javascript.

http://javascript.about.com/od/reference/g/rlong.htm