jquery - Regex to add a space after the fourth chars Javascript

Question

I have a string which is a car number plate. But for display purposes I what to add a space after the fourth char in this string. The data comes from a data service so I have to do this on the front-end

eg. AF13BXP to this AF13 BXP

The code below doesn't seem to work:

var $regtext = $('#regNumber');
if ($regtext.length > 0)
{
    var regtext = $regtext.text(),
    newRegtext = regtext.replace(/[
s]/g, '');
    console.log(newRegtext);
}

Answer 1

Simple and clear way to do this, without regex:

var $regtext = $('#regNumber');

if ($regtext.length > 0)
{
    var regtext = $regtext.text(),
    newRegtext = regtext.substr(0, 4) + " " + regtext.substr(4);
    console.log(newRegtext);
}

It's also pretty fast too: runs 10,000 times in 351ms, faster than splitting and joining etc. Good if you'll be processing loads of data from the webservice.