Yeah so I'm ALWAYS forgetting how to do this, and end up trawling through code to find where I've done it before and copy pasting. So I'm basically writing this for myself to have a centralised copy paste place.

text overflow ellipsis

/*HTML (the easy part)*/
<ul> 
    <li>Daniel Furze</li> 
    <li class="ellipsis">Mc Testerson Longname IV</li> 
</ul>

/*CSS (still a pretty easy part)*/
.ellipsis{
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}