Did you know there is two kinds of 'dashes' in punctuation? The em-dash and the en-dash. The en-dash is the more commonly used symbol. This is probably because it has a dedicated key on the standard English keyboard.
The em-dash can be typed a couple of different ways, but they are less straightforward.
Firstly, press the ALT key and type 0151 on your number pad. These numbers must be typed on your number pad and not the numbers along the top of your keyboard. On the Mac, press Shift-Option and the minus key to make en em-dash.
Secondly, Microsoft Word will automatically convert two hyphens into an em-dash when typed directly between two words. Two hyphens on their own will not be converted, they must be surrounded by words.
Thirdly, you can select from the Insert / Symbol menu in Word.
Apparently, the two symbols can be used interchangeably because there is no grammatical difference between the them. However, their implementation has some differences. You've probably already tried one of the ways to insert the em-dash I mentioned above. Notice that spaces are removed from before and after the em-dash? This is the correct grammatical use of the symbol. There must be no preceding or following spaces. This is in direct contrast to the en-dash which should have spaces before and after.
You can insert the em-dash symbols in HTML by using the HEX text of
Til next time ...