SO - 21097389

JoshC

HTML

<p id="el">Here's how it is: Earth got used up, so we terraformed a whole new galaxy of Earths, some rich and flush with new technologies, some not so much. Central Planets, them as formed the Alliance, waged war to bring everyone under their rule; a few idiots tried to fight it, among them myself. I'm Malcolm Reynolds, captain of Serenity. She's a transport ship, Firefly class. Got a good crew: fighters, pilot, mechanic. We even picked up a preacher for some reason, and a bona fide companion. Here's how it is: Earth got used up, so we terraformed a whole new galaxy of Earths, some rich and flush with new technologies, some not so much. Central Planets, them as formed the Alliance, waged war to bring everyone under their rule; a few idiots tried to fight it, among them myself. I'm Malcolm Reynolds, captain of Serenity. She's a transport ship, Firefly class. Got a good crew: fighters, pilot, mechanic. We even picked up a preacher for some reason, and a bona fide companion.</p>

CSS

#el:first-line {
    color:red;
    font-style:italic;
    font-weight:bold;
}
#el:first-letter {
    font-size:3em;
    font-style:normal;
}
#el {
    border:10px solid;
    padding:150px;
}

JavaScript

function first_line(element) {
    var el = document.getElementById(element), cache = text = el.innerHTML;
    el.innerHTML = 'a'; var initial = el.offsetHeight; el.innerHTML = cache;
    arr = text.split(" ");
    for (var i = 0; i < arr.length; i++) {
        text = text.substring(0, text.lastIndexOf(" "));
        if (el.offsetHeight == initial) {
            var temp = el.innerHTML;
            el.innerHTML = cache;
            return temp;
        }
        el.innerHTML = text;
    }
}
alert(first_line('el'));