css - Grid layout on <fieldset>... Bug on chrome?

Question

From my decades-long experience of hand-coding HTMLs, I have learnt that <form>, <fieldset> are just block-level elements like <div>. CSS-wise, they behave just the same in terms of positioning and sizing. (Please bear with me, I am ignoring old browsers like IE6 here. ) .... or so I thought....

*Before I go on, I have to state that I use Firefox for development and testing most of the time.

I was on a project with a lot of <form> and <fieldset> all over the place. To simplify my question here, I have something like:

<form>
  <fieldset>
    <div class="gridChild">...</div>
    <div class="gridChild">...</div>
    <div class="gridChild">...</div>
  </fieldset>
</form>

I wanted to have the gridChild divs to be in layout of individual columns. So I had the CSS something like:

fieldset {
  display: grid;
  grid-template-columns: 50px 2fr 6fr 6fr auto ....;
} 

And it worked. It showed the columns perfectly on my screen... It works on Firefox, Android and even Edge. The deadline was overdue. I was in rush and I didn't test it on Chrome. I thought that if Firefox and Edge works fine, then Chrome should work too, right? Or so I thought... Later on, I discovered that that doesn't work on Chrome. The grid layout is completely ignored on Chrome. I spent days just to debug the problem.

After a few sleepless nights, I found out that display:grid doesn't work on <fieldset>. It has to be applied to <div> for Chrome to work. That was a surprise for me, because I have been doing so many CSS positioning, like floating, absolute-positioning, etc in a cross-browser fashion with <form> and <fieldset>, and they have been behaving just like <div> all the time. But why not the Grid layout? Is this a bug for Chrome, or is this behaviour designed to be like that? Because I see that this is not a problem for Firefox, Edge and Android.

An easy fix I can think of is to wrap a <div> inside <fieldset>, like this:

<form>
  <fieldset><div class="gridParent">
    <div class="gridChild">...</div>
    <div class="gridChild">...</div>
    <div class="gridChild">...</div>
  </div></fieldset>
</form>

But as I said before, I have <form> and <fieldset> all over the place. It would be best if I can avoid changing the HTML structures. I am writing here to seek for a CSS solution/hack, so I don't have to go through and rewrite hundreds of HTML lines.

Answer 1

Another workaround for this issue is to use the form as the grid object and use display: contents on the fieldset. This doesn't break semantic markup, though if there are multiple elements within the form they will all be included in the grid.

.some-form {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
}

.some-form__fields {
  display: contents;
}

<form class="some-form">
  <fieldset class="some-form__fields">

    <label>
      First Name
      <input type="text"/>
    </label>
    <label>
      Last Name
      <input type="text"/>
    </label>
    <label>
      Favourite snack
      <input type="text"/>
    </label>
    
    <label>
      Favourite color
      <input type="text"/>
    </label>

  </fieldset>
</form>