function fontSize(is_smaller) {
	var id = 'main_content';
	var id_home = 'center';
	var min_size = 0.8;
	var max_size = 1.6;
	var step = 0.2;
	var default_size = 1;
	var current_size = default_size;

	var p = document.getElementById(id);
	if (!p) p = document.getElementById(id_home);
	if (p) {
		var s = (p.style.fontSize) ? parseFloat(p.style.fontSize.replace("em","")) : default_size;
		if (is_smaller) {
			s -= step;
			if (s >= min_size)
				p.style.fontSize = s+"em";
		}
		else {
			s += step;
			if (s <= max_size)
				p.style.fontSize = s+"em";
		}
	}
}

function fontBigger() {
	fontSize(false);
}


function fontSmaller() {
	fontSize(true);
}


function externalLinks() {
 if (!document.getElementsByTagName) return;
 var anchors = document.getElementsByTagName("a");
 for (var i=0; i<anchors.length; i++) {
   var anchor = anchors[i];
   if (anchor.getAttribute("href") &&
       anchor.getAttribute("rel") == "external")
     anchor.target = "_blank";
 }
}
window.onload = externalLinks;