Monthly Archives: May 2015

Online security basics: Clicking & downloading

Screenshot of Security Now video episodeNow our child is using computers and the web more and more, I’ve been thinking a lot about protecting children on the internet. There seems to be an endless list of things you should and shouldn’t do but I was struck by some simple advice in the latest Security Now episode (#507) that provides a lot of protection to start you off.

Regarding clicking links in emails, from 1:39:10 in the show Steve Gibson makes the distinction between mails that you’re expecting and mails that you’re not. In other words:

Don’t click links in emails that you weren’t expecting.

For example…

  • Probably safe: You register on a website and then get a confirmation email from them.
  • Probably safe: Your dad is looking to buy a motorbike and sends you a link to one on eBay.
  • Possible evil trap: An email from PayPal asks you to verify your details. To stay safe, you should go to PayPal’s site directly without clicking the email link.

Steve then goes on to mention another security expert, Brian Krebs, with this piece of advice:

Don’t download something you didn’t go looking for.

Super-sensible advice that actually works offline as well, for example in not signing up to financial offers and deals that you weren’t previously considering. Brian also has more basic rules for online safety that I recommend.

So there you go kids, follow these two rules and you’ll save yourself — and your nervous parents — a lot of trouble:

  1. Don’t click links in emails that you weren’t expecting.
  2. Don’t download something you didn’t go looking for.

Song: Oh! Selector ♪


Get high quality versions of this song from iTunes and Bandcamp.
Also, free not-quite-so-high quality downloads are available from SoundCloud and


Now when I was a young boy startin' out in this industry
I remember this pearl of wisdom that the internet gave to me.
To manipulate or decorate something on a web page
First ya gotta grab it and there's pretty much just one way...

Oh selector, oh won't you fetch for me
With your magic sense, all the elements within the old DOM tree.

Now selectors can be used in CSS, oh but there's more.
In plain ol' JavaScript as well with querySelector().
And don't forget the libraries like jQuery and so
You could say that they're essential if you wanna be a pro.


The next step on your journey is to learn selector syntax.
There's not much to remember so don't worry, just relax.
You start with a plain ol' tag name if you want it to be styled,
Use "plus" for adjacent sibling and "greater than" for a child.


A dot is for a class name and for IDs it's a hash.
Use square brackets for attributes and you're sure to find a match.
Now :hover needs a colon like :focus and :target.
There's other stuff as well but that's enough to get you started.


One final word of warning for my song to be complete.
Remember please that all IDs have got to be unique.
They're bad 'n' they're mean and they don't fight clean and you're gonna find it tough
If you use more than one of each because this DOM ain't big enough.

[Chorus x 2]