Demo for an SO answer

SO question: http://stackoverflow.com/questions/12917750/getting-the-last-entered-word-from-a-contenteditable-div/12918193

HTML

<div contenteditable="true">Add text here</div>

JavaScript

$("div").on("keyup", function(){
    var words = $(this).text().trim().split(' '),
        lastWord = words[words.length - 1];
    console.log(lastWord);
});