Why not to use italics online

First an admission - I do sometimes use italics. Sometimes they're just the right formatting to use, because you need to add emphasis in the literary sense. If all you want to do is highlight something, though, make bold your go-to formatting.

There are a couple of reasons for this - bold tends to clearly mark something out as being important, whereas italics can look a bit wishy-washy, especially with serif or handwriting fonts.

Most importantly though, is the risk of a rogue scrollbar appearing at the bottom of the screen. This might be less of a problem with newer browsers, but with earlier versions of Internet Explorer in particular I know it happened.

The problem is that the line width is based on the bottom of the characters, whereas the display width is based on everything that is drawn - not just the width of the character at the baseline, but also at the top.

With italics, that can mean the top-right of the character extends beyond the end of the line that it's on. It doesn't wrap, as its base is still within the limits of the line, but it causes the display of the page to become a few pixels wider.

Suddenly, if your italics are at the end of a line, your fluid layout has found a way to run off of the right-hand edge of the screen, and a scrollbar - with only a few pixels of movement in either direction - pops up at the bottom of the screen.

With the right margins and padding, I'm sure this isn't a major problem as you can easily terminate your main content before it gets that close to the edge of the screen. But if you're not certain, you may as well play it safe and use bold instead.

NB Need I tell you why not to use underlining online? It's for the same reason you wouldn't put a word in blue to add emphasis - regardless of the colour scheme of your site, a blue, underlined word looks like a hyperlink. Worse, it looks like a hyperlink with no CSS applied to it. Save underlining for links and italics for literary emphasis, and let bold be your workhorse where emphasis is concerned.