Extracting a specific section of a string via JavaScript

Question

I'm currently messing with the tumblr API for a project.

The problem I seem to have is I have to be able to extract the username from the src url eg

http://(you).tumblr.com/api/read/json

I looked into using something like substr() but I can't guarantee the number of characters to extract.

Any ideas?

Answer 1

using the regular expression:

> var s = 'http://you.tumblr.com/api/read/json';
> var re = /^http:\/\/(\w+)\./;
> s.match(re);
[ 'http://you.',
  'you',
  index: 0,
  input: 'http://you.tumblr.com/api/read/json' ]
> s.match(re)[1]
'you'

in short:

'http://you.tumblr.com/api/read/json'.match(/^http:\/\/(\w+)\./)[1]

will evaluate to

'you'

to elaborate:

^            match start of string
http:\/\/    match http://
(\w+)        match group of word characters which appears 1 or more times
\.           match a dot

Answer 2

Here's a quick and dirty way without using a regex.

var str = "http://mydomain.tumblr.com/api/read/json";
var domainpart = str.substr(7, str.indexOf(".") - 7);
document.write(domainpart);