js控制字體大小以適應頁面

<script type="text/javascript">

	cwidth = 550.0;  //頁面默認寬度
            //JS監聽瀏覽器文字大小代碼
	(function (doc, win) {
                var docEl = doc.documentElement,
                    resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize',
                    recalc = function () {
                        var clientWidth = docEl.clientWidth;
                        if (!clientWidth) return;
                        rate = (clientWidth / cwidth) ;
			cwidth = clientWidth*1.0;
			changeFont(rate);
                    };

                if (!doc.addEventListener) return;
                win.addEventListener(resizeEvt, recalc, false);
                doc.addEventListener('DOMContentLoaded', recalc, false);
            })(document, window);

	function changeFont(rate)
	{
		var child_arr = document.querySelectorAll('body *');
		for(var i=0;i<child_arr.length;i++)
		{
			if(child_arr[i].style.fontSize != "")
			{
				font=child_arr[i].style.fontSize.replace("px","");
				child_arr[i].style.fontSize = font*rate;
			}
		}

	}
</script>