How to prevent column break within an element?

Question

Consider the following HTML:

<div class='x'>
    <ul>
        <li>Number one</li>
        <li>Number two</li>
        <li>Number three</li>
        <li>Number four is a bit longer</li>
        <li>Number five</li>
    </ul>
</div>

and the following CSS:

.x {
    -moz-column-count: 3;
    column-count: 3;
    width: 30em;
}

As it stands, Firefox currently renders this similarly to the following:

• Number one    • Number three          bit longer
• Number two    • Number four is a    • Number five

Notice that the fourth item was split between the second and third column. How do I prevent that?

The desired rendering might look something more like:

• Number one    • Number four is a
• Number two      bit longer
• Number three  • Number five

or

• Number one    • Number three        • Number five
• Number two    • Number four is a
                  bit longer

Edit: The width is only specified to demonstrate the unwanted rendering. In the real case, of course there is no fixed width.

Answer 1

I had the same problem i think and found a solution in this:

-webkit-column-fill: auto; /* Chrome, Safari, Opera */
-moz-column-fill: auto; /* Firefox */
column-fill: auto;  

Working also in FF 38.0.5: http://jsfiddle.net/rkzj8qnv/

Answer 2

I just fixed some divs that were splitting onto the next column by adding

overflow: auto

to the child divs.

*Realized it only fixes it in Firefox!

Answer 3

I made an update of the actual answer.

This seems to be working on firefox and chrome: http://jsfiddle.net/gatsbimantico/QJeB7/1/embedded/result/

.x{
columns: 5em;
-webkit-columns: 5em; /* Safari and Chrome */
-moz-columns: 5em; /* Firefox */
}
.x li{
    float:left;
    break-inside: avoid-column;
    -webkit-column-break-inside: avoid;  /* Safari and Chrome */
}

Note: The float property seems to be the one making the block behaviour.

Answer 4

The following code works to prevent column breaks inside elements:

-webkit-column-break-inside: avoid;
-moz-column-break-inside: avoid;
-o-column-break-inside: avoid;
-ms-column-break-inside: avoid;
column-break-inside: avoid;