Is it better to not render HTML at all, or add display:none?

Question

As far as I understand, not rendering the HTML for an element at all, or adding display:none, seem to have exactly the same behavior: both make the element disappear and not interact with the HTML.

I am trying to disable and hide a checkbox. So the total amount of HTML is small; I can't imagine performance could be an issue.

As far as writing server code goes, the coding work is about the same.

Given these two options, is one better practice than the other? Or does it not matter which I use at all?

Answer 1

As far as I understand, not rendering the HTML for an element at all, or adding display:none, seem to have exactly the same behavior: both make the element disappear and not interact with the HTML.

No, these two options don’t have "exactly the same behavior".

If you hide an element with CSS (display:none), it will still be rendered for

• user agents that don’t support CSS (e.g., text browsers), and
• user agents that overwrite your CSS (e.g., user style sheets).

So if you don’t need it, don’t include it.

If, for whatever reason, you have to include the element, but it’s not relevant for your document/users (no matter in which presentation), then use the hidden attribute. By using this attribute, you give the information on the HTML level, hence CSS support is not needed/relevant.
You might want to use display:none in addition (this is what many CSS supporting user agents do anyway, but it’s useful for CSS-capable user agents that don’t support the hidden attribute).
You could also use the aria-hidden state in addition, which could be useful for user agents that support WAI-ARIA but not the hidden attribute.

Answer 2

I'm not a fan of adding markup to your HTML that cannot be seen and serves no purpose. You didn't provide a single benefit of doing that in your question and so the simple answer is: If you don't need a checkbox to be part of the page, then don't include it in your markup.

I suspect that a hidden checkbox will not add any noticeable time to the download or work by the server. So I agree it's not really a consideration. However, many pages do have extra content (comments, viewstate, etc.) and it can all add up. So anyone with the attitude that they will go ahead and add content that is not needed and never seen by the user, I would expect them to create pages that are noticeably slower overall.

Now, you haven't provided any information about why you might want to include markup that is not needed. Although you said nothing about client script, the one case where I might leave elements in a page that are hidden is when I'm writing client script to remove them. In this case, I may hide() it and leave in the markup. One reason for that is that I could easily show it again if needed.

That's my answer, but I think you'd get a much better answer if you described what considerations you had for including markup on the page that no one will see. Surely, it must offer some benefit that you haven't disclosed or you would have no reason to do it.

Answer 3

The confusion point here is this: Why would you ever use display: none instead of simply not render something?

To which the answer is: because you're doing it client side!

"display: none" is better practice when you're doing client side manipulations where the element might need to disappear or reappear without an additional trip to the server. In that case, it is still part of the logical structure of the page and easier to access and manipulate it than remove (and then store in memory in Javascript) and insert it.

However if you're using a server-side heavy framework and always have the liberty of not rendering it, yes, display:none is rather pointless.

• Go with "display:none" if the client has to do the work, and manage its relation to the DOM
• Go with not rendering it if every time the rendered/not rendered decision changes, the server is generating fresh (and fairly immutable) HTML each time.

Answer 4

The only positive thing I see in hiding it is in the case where you might want to add it back in later as a result of a button being clicked or something else activating it in the page. Otherwise it is just making your code needlessly longer.

Answer 5

For such a tiny scenario the result would be practically the same. But hiding the controls with CSS is IMO not something that you want to make a habit of.

It is always a good idea to make both the code and its output efficient to the point that is practical. So if it's easy for you to not include some controls in the output by adding a little condition everything can be managed tidily, try to do so. Of course this would not extend to the part of your code that receives input, because there you should always be ready to handle any arbitrary data (at least for a public app).

On the other hand, in some cases the code that produces the output is hard to modify; in particular, giving it the capability to determine what to do could involve doing damage in the form of following bad practices: perhaps add a global variable, or else modify/override several functions so that the condition can be transferred through. It's not unreasonable in that case to just add a little CSS in order to again, achieve the solution in a short and localized manner.

It's also interesting to note that in some cases the decision can turn out to be based on hard external factors. For example, a pretty basic mechanism of detecting spambots is to include a field that appears no different in HTML than the others but is made invisible with CSS. In this situation a spambot might fill in the invisible field and thus give itself away.

Answer 6

I mean do you need that checkbox? If not then .hide() is just brushing things under the carpet. You are making your HTML cluttered as well as your CSS. However, if it needs to be there then sure, but if you can do without the checkbox then I would not have it in the HTML.

Keep it simple and readable.