function showBlogLayer() {
	showLayer('blogLayer');
	hideLayer('newsLayer');
	hideLayer('tbLayer');
	bgImageOn('blogDataBoxBlogTab', 'blog');
	bgImageOff('blogDataBoxNewsTab', 'news');
}
function showNewsLayer() {
	hideLayer('blogLayer');
	showLayer('newsLayer');
	hideLayer('tbLayer');
	bgImageOff('blogDataBoxBlogTab', 'blog');
	bgImageOn('blogDataBoxNewsTab', 'news');
}
function showTbLayer() {
	hideLayer('blogLayer');
	hideLayer('newsLayer');
	showLayer('tbLayer');
	bgImageOff('blogDataBoxBlogTab', 'blog');
	bgImageOff('blogDataBoxNewsTab', 'news');
}


// --Util
function showLayer(sDivId) {
	if (document.all) {
		document.all(sDivId).style.display = 'block';
	}
	else if (document.getElementById) {
		document.getElementById(sDivId).style.display = 'block';
	}
}

function hideLayer(sDivId) {
	if (document.all) {
		document.all(sDivId).style.display = 'none';
	}
	else if (document.getElementById) {
		document.getElementById(sDivId).style.display = 'none';
	}
}

function bgImageOn(sTargetId, sBgClassName) {
	var oTarget;
	
	if (document.all) {
		oTarget = document.all(sTargetId);
	}
	else if (document.getElementById) {
		oTarget = document.getElementById(sTargetId);
	}
	oTarget.className = sBgClassName + '-on';
}
function bgImageOff(sTargetId, sBgClassName) {
	var oTarget;
	
	if (document.all) {
		oTarget = document.all(sTargetId);
	}
	else if (document.getElementById) {
		oTarget = document.getElementById(sTargetId);
	}
	oTarget.className = sBgClassName + '-off';
}