javascript 让所有页面内容都有淡入淡出效果

关于淡入淡出效果的实现，本站已经有文章介绍过，而本文介绍的是通过 javascript ，让所有的页面内容（可以设置背景色的元素）都能有淡入淡出效果，而我们需要做的只是给需要效果的元素设置ID和 className 。按照一定规则，你可以随意定义淡入淡出的颜色。

javascript 让所有页面内容都有淡入淡出效果 – 示例

<script type="text/javascript">
<!--
// 说明：用 javascript 让所有页面内容都有淡入淡出效果
// 整理：http://www.codebit.cn

// @name      The Fade Anything Technique
// @namespace http://www.axentric.com/aside/fat/
// @version   1.0-RC1
// @author    Adam Michela

var Fat = {
	make_hex : function (r,g,b)
	{
		r = r.toString(16); if (r.length == 1) r = '0' + r;
		g = g.toString(16); if (g.length == 1) g = '0' + g;
		b = b.toString(16); if (b.length == 1) b = '0' + b;
		return "#" + r + g + b;
	},
	fade_all : function ()
	{
		var a = document.getElementsByTagName("*");
		for (var i = 0; i < a.length; i++)
		{
			var o = a[i];
			var r = /fade-?(\w{3,6})?/.exec(o.className);
			if (r)
			{
				if (!r[1]) r[1] = "";
				if (o.id) Fat.fade_element(o.id,null,null,"#"+r[1]);
			}
		}
	},
	fade_element : function (id, fps, duration, from, to)
	{
		if (!fps) fps = 30;
		if (!duration) duration = 3000;
		if (!from || from=="#") from = "#FFFF33";
		if (!to) to = this.get_bgcolor(id);

		var frames = Math.round(fps * (duration / 1000));
		var interval = duration / frames;
		var delay = interval;
		var frame = 0;

		if (from.length < 7) from += from.substr(1,3);
		if (to.length < 7) to += to.substr(1,3);

		var rf = parseInt(from.substr(1,2),16);
		var gf = parseInt(from.substr(3,2),16);
		var bf = parseInt(from.substr(5,2),16);
		var rt = parseInt(to.substr(1,2),16);
		var gt = parseInt(to.substr(3,2),16);
		var bt = parseInt(to.substr(5,2),16);

		var r,g,b,h;
		while (frame < frames)
		{
			r = Math.floor(rf * ((frames-frame)/frames) + rt * (frame/frames));
			g = Math.floor(gf * ((frames-frame)/frames) + gt * (frame/frames));
			b = Math.floor(bf * ((frames-frame)/frames) + bt * (frame/frames));
			h = this.make_hex(r,g,b);

			setTimeout("Fat.set_bgcolor('"+id+"','"+h+"')", delay);

			frame++;
			delay = interval * frame;
		}
		setTimeout("Fat.set_bgcolor('"+id+"','"+to+"')", delay);
	},
	set_bgcolor : function (id, c)
	{
		var o = document.getElementById(id);
		o.style.backgroundColor = c;
	},
	get_bgcolor : function (id)
	{
		var o = document.getElementById(id);
		while(o)
		{
			var c;
			if (window.getComputedStyle) c = window.getComputedStyle(o,null).getPropertyValue("background-color");
			if (o.currentStyle) c = o.currentStyle.backgroundColor;
			if ((c != "" && c != "transparent") || o.tagName == "BODY") { break; }
			o = o.parentNode;
		}
		if (c == undefined || c == "" || c == "transparent") c = "#FFFFFF";
		var rgb = c.match(/rgb\s*\(\s*(\d{1,3})\s*,\s*(\d{1,3})\s*,\s*(\d{1,3})\s*\)/);
		if (rgb) c = this.make_hex(parseInt(rgb[1]),parseInt(rgb[2]),parseInt(rgb[3]));
		return c;
	}
}

window.onload = function () {
	Fat.fade_all();
}
//-->
</script>

给你希望有淡入淡出效果的元素设置一个值为 fade 的 className，如：class="fade"，默认的淡入淡出颜色是 #FFFF33，如果你想用其他颜色，只需要在 className 后面加上 "-你期望的颜色"，如：class="fade-0000FF"，这样的话，淡入淡出的颜色就是蓝色，是不是很方便？注意，元素一定要有 ID ！