How to get IP value from textarea with regular expression

Question

Here is a textarea.(IPv4, Domain)

96.17.109.65 fox.com

And I want to change IP value into another one. like this,

74.125.71.106 fox.com

I guess it will be like

$('textarea').find('some regular expressions..').val('another one...');

Please help me. I just wanna learn regular expressions.. thanks.

Answer 1

Matching an IP address using regular expression is not as easy as it sounds. There are two methods available:

simple, but can lead to false-positives:

\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b

complex, but always correct:

\b(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b

If you want to replace it, you'll need something like this (using the simple RegExp as an example):

var textarea = $('textarea');
textarea.val(textarea.val().replace(/\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b/g, '74.125.71.106'));