/*環境設定*/
var displayNum = 5;		//表示数
var displayStep = 5;	//表示ステップ
var curPos = -1;			//カレントポジション

/*オブジェクト読み込み*/
var topicsObj = document.getElementById("topics");
var topicsListObj = crossBrowserLastChild(topicsObj);
var topicsChildObj = topicsListObj.children;
for (i=0; i<topicsChildObj.length; i++){
	topicsChildObj[i].style.display = "none";
	if (Effect.prototype.Browser_find() == "MSIE"){
		topicsChildObj[i].style.filter = "alpha(opacity=0)";
	} else {
		topicsChildObj[i].style.opacity = "0";
	}
}

listDisplay();

/*ボタンオブジェクト追加*/
var scrollButton = document.createElement("div");
scrollButton.id = "more";
topicsObj.appendChild(scrollButton);
scrollButton = crossBrowserLastChild(topicsObj);
var scrollLink = document.createElement("a");
scrollButton.appendChild(scrollLink);
scrollLink = scrollButton.firstChild;
scrollLink.href = "javascript:topicsDisplay();";

/*トピックス表示*/
function topicsDisplay(){
	displayNum+= displayStep;
	if (displayNum >= topicsChildObj.length / 2){
		displayStep-= displayNum - topicsChildObj.length/2;
		scrollButton.style.display = "none";
	}
	listDisplay();
}

function listDisplay(){
	for (i=0; i < displayStep*2; i++){
		curPos++;
		topicsChildObj[curPos].style.display = "block";
		alpha(topicsChildObj[curPos],100,16,"down");
	}
}

/*ブラウザ別LastElementChild動作適性振り分け*/

function crossBrowserLastChild(pObj){
	switch(Effect.prototype.Browser_find()){

		case "MSIE":
			return pObj.lastChild;
			break;
		
		case "Gecko":
			return pObj.lastElementChild;
			break;
			
		case "Safari":
			return safariLastChild(pObj);
			break;
	}
}

/*lastElementChild ver.Safari*/

function safariLastChild(tObj){
	var chiNode = tObj.children;
	var i = chiNode.length-1;
	return chiNode[i];
}