<div id="more" onclick="swap()">click to read more...</div>
<div  id="wrap">This is a wrapping div which can have a lot of content. It replaces the "click to read more..." text.</div>

#wrap {display:none;}
#more {cursor:pointer;}

function swap() {
document.getElementById("wrap").style.display = 'block';
document.getElementById("more").style.display = 'none';
}