winSize = 200;
openMsg = "プレビュー";
closeMsg = "閉じる";

function IsOverlappedOnSC(span) {
	if (!span) return true;

	var sc = document.all['sc'];
	if (!sc) return true;

	var scTop = document.body.clientTop + sc.offsetTop;
	var scBottom = scTop + sc.offsetHeight;

	var spanTop = document.body.clientTop + span.offsetTop;
	var spanBottom = spanTop + winSize;

	if (spanBottom <scTop || scBottom < spanTop) return false;
	return true;
}

function PreView(url) {
	var ifID = 'if' + url.id;
	var tbID = 'tb' + url.id;

	var spanObj = url.parentElement;
	if (!spanObj) return true;
	if (spanObj.tagName.toLowerCase() != 'span') return true;

	var ifObj = document.all[ifID];

	if (url.innerText == openMsg) {
		url.innerText = closeMsg;
		var strAnchor = '- ' + url.outerHTML;

		if (ifObj) {
			ifObj.style.visibility = 'visible';
			ifObj.style.height = winSize;
			return false;
		}

		var strIFrame = '<IFRAME id="'+ifID+'" width="95%" height="'+winSize+'" SRC="'+url.href+'"></IFRAME>';

		if (IsOverlappedOnSC(url)) {
			spanObj.innerHTML = strAnchor + '<table id="'+tbID+'" width="95%" border="0" align="center"><tr><td>' + strIFrame + '</td></tr></table>';
			return false;
		} else {
			spanObj.innerHTML = strAnchor + strIFrame;
			return false;
		}

	} else {
		if (url) {
			url.innerText = openMsg;
			spanObj.innerHTML = '- ' + url.outerHTML;
			var tbObj = document.all[tbID];
			if (tbObj) {
				return false;
			}
			if (ifObj) {
				ifObj.style.visibility = 'hidden';
				ifObj.style.height = 0;
			}
			return false;
		}
	}
	return true;
}