var body = document.body;
fontSizing();
addEvent(window,'resize',fontSizing);
function fontSizing(){
var curWidth = 1024;
var currSize = 0.8;
currSize = body.offsetWidth * currSize / curWidth;
currSize = currSize < 0.8 ? 0.8 : currSize;
currSize = currSize > 1.0 ? 1.0 : currSize;
body.style.fontSize = currSize + 'em';
}

function addEvent(elementPtr, eventType, eventFunc) {
if (elementPtr.addEventListener)
elementPtr.addEventListener(eventType, eventFunc, false);
else
elementPtr.attachEvent('on' + eventType, eventFunc); }