Can I style numbering an ordered list that has a start attribute value?

Question

Here's the problem:

I have an ol li ordered list with a start attribute like so:

    .custom {
      margin: 0;
      padding: 0;
      list-style-type: none;
    }
    
    .custom li {
      counter-increment: step-counter;
      margin-bottom: 10px;
    }
    
    .custom li::before {
      content: counter(step-counter);
      margin-right: 5px;
      font-size: 80%;
      background-color: rgb(0,200,200);
      color: white;
      font-weight: bold;
      padding: 3px 8px;
      border-radius: 3px;
    }

    <ol start="6" class="custom">
      <li>This is the sixth item</li>
      <li>This is the seventh item</li>
      <li>This is the eighth item</li>
      <li>This is the ninth item</li>
      <li>This is the tenth item</li>
    </ol>

I get the following output on the browser:

Is it possible to serialize the list-style numbering on an ordered list using the value in start attribute instead of 1? No JavaScript can be used for this though.

Smitten

Answer 1

You can simulate this using CSS variable that you set instead of start and use it to reset the counter. For semantic purpose you can also keep start attribute.

.custom {
  margin: 0;
  padding: 0;
  list-style-type: none;
  counter-reset: step-counter calc(var(--start) - 1);
}

.custom li {
  counter-increment: step-counter;
  margin-bottom: 10px;
}

.custom li::before {
  content: counter(step-counter);
  margin-right: 5px;
  font-size: 80%;
  background-color: rgb(0, 200, 200);
  color: white;
  font-weight: bold;
  padding: 3px 8px;
  border-radius: 3px;
}

<ol style="--start:6" start="6" class="custom">
  <li>This is the sixth item</li>
  <li>This is the seventh item</li>
  <li>This is the eighth item</li>
  <li>This is the ninth item</li>
  <li>This is the tenth item</li>
</ol>

Comedic

Using CSS variables is interesting but it does affect the semantics. How would ` style="--start:6" ` instead of start="6" be seen on a screen reader for example? – Smitten

Cool. This solution is now in use on production on this book from page number 43 onwards: bubblin.io/book/meditations-by-marcus-aurelius/43 Thanks @temani-afif :-) – Smitten

Answer 2

li tag have no access to parent attribute.

This is the best way i saw, using content: attr()

    .custom {
      margin: 0;
      padding: 0;
      list-style-type: none;
    }
    
    .custom li {
      counter-increment: step-counter;
      margin-bottom: 10px;
    }
    
    .custom li::before {
      content: attr(data-idx);
      margin-right: 5px;
      font-size: 80%;
      background-color: rgb(0,200,200);
      color: white;
      font-weight: bold;
      padding: 3px 8px;
      border-radius: 3px;
    }

    <ol class="custom">
      <li data-idx="6">This is the sixth item</li>
      <li data-idx="7">This is the seventh item</li>
      <li data-idx="8">This is the eighth item</li>
      <li data-idx="9">This is the ninth item</li>
      <li data-idx="10">This is the tenth item</li>
    </ol>

Venessavenetia

Answer 3

I've added a few rules to your CSS. The most important is this:

.custom{counter-reset:start 5;} 

This will make the list to start at 5+1 = 6

.custom {
  margin: 0;
  padding: 0;
  list-style-type: none;
  counter-reset:start 5;/*This*/
}

.custom li {
  counter-increment: step-counter;
  margin-bottom: 10px;
  counter-increment: start;/*This*/
}

.custom li::before {
  content:counter(start);/*This*/
  margin-right: 5px;
  font-size: 80%;
  background-color: rgb(0,200,200);
  color: white;
  font-weight: bold;
  padding: 3px 8px;
  border-radius: 3px;
}

<ol class="custom">
  <li>This is the sixth item</li>
  <li>This is the seventh item</li>
  <li>This is the eighth item</li>
  <li>This is the ninth item</li>
  <li>This is the tenth item</li>
</ol>

Willin

This makes every list start at 6 instead of interpreting the start value from the HTML. – Laveralavergne

Exactly, thats just moving the problem, not making it work with things like WYSIWYGs – Evers

Answer 4

Here is my jank solution.

Prepend with js x li's at the beginning of the ol. Then hide them by positionning them absolute and throwing them to the moon.

$('ol[start]').each(function(){
    var start = $(this).attr('start');
    //console.log(start);
    for(var i=1;i<start;i++){
        $(this).prepend('<li class="hidden"></li>');
    }
})

    
ol{
  counter-reset: items;
  padding:0;
  padding-left: 46px;
}
ol  li {
  display: block;
  counter-increment: items;
  text-indent: -22px;
  margin-bottom: 25px;
}

ol li.hidden{
  visibility:hidden;
  position:absolute;
  left:-999vw;
}

ol li:before {
    content: "0" counter(items)". ";
    color:green;
    display:inline-block;
    width:22px;
    font-size:14px;
}

ol li:nth-child(n+10):before {
    content: "" counter(items)". ";
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<ol start="4">
  <li>Item 4</li>
  <li>Item 5</li>
  <li>Item 6</li>
  <li>Item 7</li>
  <li>Item 8</li>
  <li>Item 9</li>
  <li>Item 10</li>
</ol>

Evers