I good way of doing it is having "overflow-y: scroll" on your article HTML element and then removing text until the ".scrollHeight == .offsetHeight" of the HTML element.
Here's the straight JavaScript.
var all = document.getElementsByTagName("div");
for(var i=0; i<all.length; i++) {
var article = all[i];
if(article.className && /(^|\s)article($|\s)/.test(article.className)) {
article.scrollTop = 1;
var cnt = 0;
while(article.scrollTop != 0 || article.scrollHeight != article.offsetHeight) {
cnt++; if(cnt > 50) break;
var ps = article.getElementsByTagName("p");
if(ps.length == 0)
break;
var p = ps[ps.length - 1];
var shorter = p.innerHTML;
var idx = shorter.lastIndexOf(" ");
shorter = idx >= 0 ? shorter.substring(0, idx) : "";
p.innerHTML = shorter;
if(p.innerHTML.length == 0)
article.removeChild(p);
article.scrollTop = 1;
}
article.style.overflowY = "hidden";
}
}