//with prototype.js library
Event.observe(window, 'load', changeBrowserSize, false);
window.onresize = changeBrowserSize;

function changeBrowserSize(){
	if (document.documentElement.clientHeight) {
		gbsH = document.documentElement.clientHeight;
	}
	else if (document.all) {
		gbsH = document.body.clientHeight;
	}
	else {
		gbsH = window.innerHeight;
	}

	sbs = (gbsH<=650)?'two_column':'three_column';
	document.body.className=sbs;
};