I just saw that I have been referenced as some sort of code authority (THANX for the compliment Melanie, but any claims I might make to authority are purely bogus). At any rate, I will attempt to respond. First, as to the question of whether I provided a reference for stating that the space before the "/>" is required - I would have been quoting the HTML 4.0 standard. Although I could provide a link to it here, I am not doing that because it has been replaced by HTML 5.0. I had not studied HTML 5 in depth before, but went to look up the reference there and discovered that HTML 5 no longer requires the space. Whether or not the space is to be used is a function of something called the DOCTYPE, which is the declaration made in the first line of the file that designates the specification to be used to parse (fancy-shmancy for formatting the document for browser display) the file. We used to use the version number - (as in HTML3 or HTML4, etc) but HTML5 uses just plain HTML without any version number.
Although it may be addressed in the HTML5 Specification, I did not find it on a quick search. I did find something VERY interesting, though, HERE, where several different markup languages are explained. It explains void elements (ones that do not operate on content and therefore don't have start and end tags) with an example of a tag that creates a button as follows:
To create a button with the input element, do this if you use an XHTML doctype:
<input type="submit" value="Ok" />
And this if you use HTML:
<input type="submit" value="Ok">
Both are ok if you use HTML5.
Bottom line: It looks like the pendulum has swung and in HTML5, empty tags are shown with and without the slash, but when the slash is used it is shown with the space before it. It should be noted, though, that the coding we do here is not HTML-anything. It is wikicode, which is a crudely bastardized version (in my opinion) of a very old HTML version. WikiTree uses the WikiMedia parser (and they use an out of date version of that) to convert wikicode to XHTML 1.0 code to be displayed in our browsers. Thus, according to the above, we SHOULD be using the space!
For anyone interested, if you use your browser's "View Source" function (you can probably right click and select it in most browsers) when you are on a WikiTree page (not a G2G page), you will see the following first line:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "https://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">