function adjustStyle(){
		var width = 0;
		// get the width.. more cross-browser issues
		if (window.innerHeight) {
			width = window.innerWidth;
		} else if (document.documentElement && document.documentElement.clientHeight) {
			width = document.documentElement.clientWidth;
		} else if (document.body) {
			width = document.body.clientWidth;
		}
		// now we should have it
		if (width < 600) {
			document.getElementById("myCSS").setAttribute("href", "_css/narrow.css");
		} else {
			document.getElementById("myCSS").setAttribute("href", "_css/main.css");
		}	
}

//now call it when the window is resized.
window.onresize = function () {
	adjustStyle();
};

window.onload = function (){
	adjustStyle();
};