Ordered list (HTML) lower-alpha with right parentheses?

The default lower-alpha list type for ordered list uses a dot '.'. Is there a way to use a right parenthesis instead like a)... b) ..etc?

Here's a neat solution. (Honestly I surprised myself with this.) CSS has something called counters, where you can set, for example, automatic chapter numbers on each heading. A bit of modification gives you the below; You'll need to sort out padding etc yourself.

ol {
  counter-reset: list;
}
ol > li {
  list-style: none;
}
ol > li:before {
  content: counter(list, lower-alpha) ") ";
  counter-increment: list;
}

<span>custom list style type (v1):</span>
<ol>
  <li>Number 1</li>
  <li>Number 2</li>
  <li>Number 3</li>
  <li>Number 4</li>
  <li>Number 5</li>
  <li>Number 6</li>
</ol>

Works in all modern browsers and IE9+ (and possibly IE8 but may be buggy).

Update: I added child selector to prevent nested lists picking up the parent style. trejder also beings up a good point in the comments that the list item alignment is also messed up. An article on 456bereastreet has a good solution which involves absolutely positioning the counter.

ol {
    counter-reset: list;
}
ol > li {
    list-style: none;
    position: relative;
}
ol > li:before {
    counter-increment: list;
    content: counter(list, lower-alpha) ") ";
    position: absolute;
    left: -1.4em;
}

<span>custom list style type (v2):</span>
<ol>
  <li>Number 1</li>
  <li>Number 2</li>
  <li>Number 3</li>
  <li>Number 4</li>
  <li>Number 5</li>
  <li>Number 6</li>
</ol>

Here is a jsFiddle showing the result, including nested lists.

building off of DisgruntledGoat's answer, I expanded it to support sub lists & styles as I needed. Sharing it here in case it helps someone.

https://jsfiddle.net/0a8992b9/ outputs:

(i)first roman
    (a)first alpha
    (b)second alpha
    (c)third alpha
    (d)fourth alpha
(ii)second roman
(iii)third roman
    (a)first alpha
    (b)second alpha

More than 10 years after the original question the standard (and, to some extent, implementations) seem to have caught up.

CSS now provides ::marker pseudoclass which can be used to achieve custom list markers: MDN.

Using ::marker automatically indents li's content without any hacks. According to MDN, as of Feb 2021 it's supported in Firefox, Chrome and Edge, and partially (not for this use case) in Safari.

.container {
  width: 400px;
}

ol.custom-marker {
  counter-reset: list;
}

ol.custom-marker > li {
  list-style: none;
  counter-increment: list;
}

ol.custom-marker.parens-after.decimal > li::marker {
  content: counter(list) ")\a0";
}

ol.custom-marker.parens-around.lower-roman > li::marker {
  content: "(" counter(list, lower-roman) ")\a0";
}

<div class='container'>
  <ol class='custom-marker parens-after decimal'>
    <li>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Eu sem integer vitae justo eget magna fermentum. Quis varius quam quisque id diam.</li>
    <li>Another list here
      <ol class='custom-marker parens-around lower-roman'>
        <li>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Eu sem integer vitae justo eget magna fermentum. Quis varius quam quisque id diam.</li>
        <li>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Eu sem integer vitae justo eget magna fermentum. Quis varius quam quisque id diam.</li>
      </ol>
    </li>
    <li>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Eu sem integer vitae justo eget magna fermentum. Quis varius quam quisque id diam.</li>
  </ol>
</div>

\a0 in content is  , since ::marker doesn't support margins or padding.

Adding this to the CSS gave some interesting results. It was close, but no cigar.

li:before {
    display: inline-block;
    width: 1em; 
    position: relative;
    left: -0.5em; 
    content: ')'
}

----- Edited to include solution from Iazel, in the comments -----

I've perfected your solution:

li {
    position: relative;
}
li:before {
    display: inline-block;
    width: 7px;
    position: absolute;
    left: -12px;
    content: ')';
    background-color: #FFF;
    text-align: center;
}

The background and position: absolute did the trick!

This seems to work:

ol {
  counter-reset: list;
  margin: 0;
}

ol > li {
  list-style: none;
  position: relative;
}

ol > li:before {
  counter-increment: list;
  content: counter(list, lower-alpha) ") ";
  position: absolute;
  left: -1.4em;
}

In Firefox and newer versions of Chrome/Edge/Chromium, you can define your own counter style with @counter-style and use the prefix and suffix properties to define what comes before/after the counter. According to MDN, this still isn't supported in Safari (as of Oct 2021).

@counter-style my-new-list-style {
  system: extends lower-alpha;
  suffix: ') ';
}

.container ol {
  list-style: my-new-list-style;
}

<div class="container">
  <ol>
    <li>One.</li>
    <li>Two!</li>
    <li>Three?</li>
    <li>Four...</li>
  </ol>
</div>

This works for me in IE7, FF3.6, Opera 9.64 and Chrome 6.0.4:

<ol start="a" type="a" style="font-weight: normal;">
<li><span style="inline-block;margin-left: -9px !important; margin-left: -15px;">) &nbsp;</span> content for line number one;</li>
<li><span style="inline-block;margin-left: -9px !important; margin-left: -15px;">) &nbsp;</span>  content for line number two;</li>
<li><span style="inline-block;margin-left: -9px !important; margin-left: -15px;">) &nbsp;</span>  content for line number three;</li> 
<li><span style="inline-block;margin-left: -9px !important; margin-left: -15px;">) &nbsp;</span>  content for line number four;</li>
<li><span style="inline-block;margin-left: -9px !important; margin-left: -15px;">) &nbsp;</span>  content for line number five;</li>
<li><span style="inline-block;margin-left: -9px !important; margin-left: -15px;">) &nbsp;</span>  content for line number six;</li>
</ol>

this is inline because it is coded for an email, but the main point is that the span acts as a content block and pulls the paren into negative left territory so it lines up with the list numbers. the two margins are to compensate for IE7 and FF differences

hope this helps.