var pop = document.getElementById('popup');

var xoffset = 15;
var yoffset = 10;

document.onmousemove = function(e) {
var x, y, right, bottom;
try { x = e.pageX; y = e.pageY; } // FF
catch(e) { x = event.x; y = event.y; } // IE

right = (document.documentElement.clientWidth || document.body.clientWidth || document.body.scrollWidth);

bottom = (window.scrollY || document.documentElement.scrollTop ||
document.body.scrollTop) + (window.innerHeight ||
document.documentElement.clientHeight || document.body.clientHeight ||
document.body.scrollHeight);

x += xoffset;
y += yoffset;

if(x > right-pop.offsetWidth)
x = right-pop.offsetWidth;

if(y > bottom-pop.offsetHeight)
y = bottom-pop.offsetHeight;

pop.style.top = y+'px';
pop.style.left = x+'px';

}

function popup(text) {
pop.innerHTML = text;
pop.style.display = 'block';

}

function popout() {
pop.style.display = 'none';

}