Extract ip address from a string using regex

Question

 var r = "\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b"; //http://www.regular-expressions.info/examples.html

var a = "http://www.example.com/landing.aspx?referrer=10.11.12.13";

var t = a.match(r); //Expecting the ip address as a result but gets null

The above is my code to extract ip address from a string. But it fails to do so. Kindly advice where it fails.

wont lastIndexOf("=") + 1 subStr do? – naveen Sep 21 '15 at 07:31 — naveen, Sep 21 '15 at 07:31

score 25 · Accepted Answer · edited Jul 17 '20 at 11:00

25

You have defined r as string, initialize it as regular expression.

var r = /\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b/;

var r = /\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b/; //http://www.regular-expressions.info/examples.html

var a = "http://www.example.com/landing.aspx?referrer=10.11.12.13";

var t = a.match(r);
console.log(t[0])

edited Jul 17 '20 at 11:00

Reigel

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answered Sep 21 '15 at 07:21

Satpal

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2

the number should in between 0-255 – Liao Zhuodi Jan 12 '17 at 08:05
2

^ that is not a restriction you want to try to put in via a regex. – Mala Oct 24 '19 at 14:09

Extract ip address from a string using regex

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