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.getAttribute("rel") == "external nofollow" || 
			anchor.getAttribute("rel") == "nofollow external" )
			)
		anchor.target = "_blank";
	}
}
window.onload = function() {
	externalLinks();
}

function show_hide_box(ele)
{
	var i;

	for (i = 1; i <= 20; i++)
	{
		var tb = document.getElementById('box_' + i);
		if (ele.checked == true)
			tb.style.display = '';
		else
			tb.style.display = 'none';
	}
}