function chFontSize(type){
	var computedStyle = document.getElementById('chSize').currentStyle || window.getComputedStyle(document.getElementById('chSize'), null);
	var currFontSize = computedStyle.fontSize;
	var finalNum = parseFloat(currFontSize, 10);
	if (type == 'bigger') {
		finalNum *= 1.2;
	} else {
		finalNum /=1.2;
	}
	document.getElementById('chSize').style.fontSize = finalNum + 'px';
	document.getElementById('chSize').style.lineHeight = finalNum * 1.7 + 'px';
	return false;
}