JS实现颜色梯度与渐变效果完整实例

本文实例讲述了JS实现颜色梯度与渐变效果的方法。分享给大家供大家参考，具体如下：

运行效果图如下：

完整实例代码如下：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>JavaScript 颜色梯度和渐变效果</title>
<script type="text/javascript">
var $ = function (id) {
  return "string" == typeof id ? document.getElementById(id) : id;
};
var Extend = function(destination, source) {
 for (var property in source) {
 destination[property] = source[property];
 }
 return destination;
}
var Map = function(array, callback, thisObject){
 if(array.map){
 return array.map(callback, thisObject);
 }else{
 var res = [];
 for (var i = 0, len = array.length; i < len; i++) { res.push(callback.call(thisObject, array[i], i, array)); }
 return res;
 }
}
var ColorGrads = function(options){
 this.SetOptions(options);
 this.StartColor = this.options.StartColor;
 this.EndColor = this.options.EndColor;
 this.Step = Math.abs(this.options.Step);
};
ColorGrads.prototype = {
 //设置默认属性
 SetOptions: function(options) {
  this.options = {//默认值
 StartColor: "#fff",//开始颜色
 EndColor: "#000",//结束颜色
 Step: 20//渐变级数
  };
  Extend(this.options, options || {});
 },
 //获取渐变颜色集合
 Create: function() {
 var colors = [],
 startColor = this.GetColor(this.StartColor),
 endColor = this.GetColor(this.EndColor),
 stepR = (endColor[0] - startColor[0]) / this.Step,
 stepG = (endColor[1] - startColor[1]) / this.Step,
 stepB = (endColor[2] - startColor[2]) / this.Step;
 //生成颜色集合
 for(var i = 0, n = this.Step, r = startColor[0], g = startColor[1], b = startColor[2]; i < n; i++){
 colors.push([r, g, b]); r += stepR; g += stepG; b += stepB;
 }
 colors.push(endColor);
 //修正颜色值
 return Map(colors, function(x){ return Map(x, function(x){
 return Math.min(Math.max(0, Math.floor(x)), 255);
 });});
 },
 //获取颜色数据
 GetColor: function(color) {
 if(/^#[0-9a-f]{6}$/i.test(color))
 {//#rrggbb
 return Map([color.substr(1, 2), color.substr(3, 2), color.substr(5, 2)],
  function(x){ return parseInt(x, 16); }
 )
 }
 else if(/^#[0-9a-f]{3}$/i.test(color))
 {//#rgb
 return Map([color.substr(1, 1), color.substr(2, 1), color.substr(3, 1)],
  function(x){ return parseInt(x + x, 16); }
 )
 }
 else if(/^rgb(.*)$/i.test(color))
 {//rgb(n,n,n) or rgb(n%,n%,n%)
 return Map(color.match(/\d+(\.\d+)?\%?/g),
  function(x){ return parseInt(x.indexOf("%") > 0 ? parseFloat(x, 10) * 2.55 : x, 10); }
 )
 }
 else
 {//color
 var mapping = {"red":"#FF0000"};//略
 color = mapping[color.toLowerCase()];
 if(color){
  return Map([color.substr(1, 2), color.substr(3, 2), color.substr(5, 2)],
  function(x){ return parseInt(x, 16); }
  )
 }
 }
 }
};
var CurrentStyle = function(element){
 return element.currentStyle || document.defaultView.getComputedStyle(element, null);
}
var Bind = function(object, fun) {
 var args = Array.prototype.slice.call(arguments).slice(2);
 return function() {
 return fun.apply(object, args.concat(Array.prototype.slice.call(arguments)));
 }
}
//渐变对象
var ColorTrans = function(obj, options){
 this._obj = $(obj);
 this._timer = null;//定时器
 this._index = 0;//索引
 this._colors = [];//颜色集合
 this._grads = new ColorGrads();
 this.SetOptions(options);
 this.Speed = Math.abs(this.options.Speed);
 this.CssColor = this.options.CssColor;
 this._startColor = this.options.StartColor || CurrentStyle(this._obj)[this.CssColor];
 this._endColor = this.options.EndColor;
 this._step = Math.abs(this.options.Step);
 this.Reset();
 this.SetColor();
};
ColorTrans.prototype = {
 //设置默认属性
 SetOptions: function(options) {
 this.options = {//默认值
 StartColor: "",//开始颜色
 EndColor: "#000",//结束颜色
 Step: 20,//渐变级数
 Speed: 20,//渐变速度
 CssColor: "color"//设置属性（Scripting属性）
 };
  Extend(this.options, options || {});
 },
 //重设颜色集合
 Reset: function(color) {
 //修改颜色后必须重新获取颜色集合
 color = Extend({ StartColor: this._startColor, EndColor: this._endColor, Step: this._step }, color || {});
 //设置属性
 this._grads.StartColor = this._startColor = color.StartColor;
 this._grads.EndColor = this._endColor = color.EndColor;
 this._grads.Step = this._step = color.Step;
 //获取颜色集合
 this._colors = this._grads.Create();
 this._index = 0;
 },
 //颜色渐入
 FadeIn: function() {
 this.Stop(); this._index++; this.SetColor();
 if(this._index < this._colors.length - 1){
 this._timer = setTimeout(Bind(this, this.FadeIn), this.Speed);
 }
 },
 //颜色渐出
 FadeOut: function() {
 this.Stop(); this._index--; this.SetColor();
 if(this._index > 0){
 this._timer = setTimeout(Bind(this, this.FadeOut), this.Speed);
 }
 },
 //颜色设置
 SetColor: function() {
 var color = this._colors[Math.min(Math.max(0, this._index), this._colors.length - 1)];
 this._obj.style[this.CssColor] = "rgb(" + color[0] + "," + color[1] + "," + color[2] + ")";
 },
 //停止
 Stop: function() {
 clearTimeout(this._timer);
 }
};
</script>
</head>
<body>
<style type="text/css">
#idGrads{}
#idGrads div{ font-size:0;height:1px;}
</style>
<div id="idGrads"> </div>
<script>
var forEach = function(array, callback, thisObject){
 if(array.forEach){
 array.forEach(callback, thisObject);
 }else{
 for (var i = 0, len = array.length; i < len; i++) { callback.call(thisObject, array[i], i, array); }
 }
}
var colors = new ColorGrads({ StartColor: "#fff", EndColor: "rgb(20,127,0)" }).Create();
forEach(colors.concat().concat(colors.reverse()), function(x){
 $("idGrads").innerHTML += "<div style=\"background-color:"+"rgb(" + x[0] + "," + x[1] + "," + x[2] + ");\"></div>";
})
</script>
<Br />
<Br />
<style type="text/css">
#idMenu{ background:#DBDBDB;text-align:center;line-height:25px; table-layout:fixed;}
#idMenu td{ cursor:pointer;}
</style>
<table id="idMenu" width="600" border="0" cellspacing="5" cellpadding="0">
 <tr>
 <td onclick="location.href='#'">Cropper</td>
 <td onclick="location.href='#'">Tween</td>
 <td onclick="location.href='#'">Slider</td>
 <td onclick="location.href='#'">Resize</td>
 <td onclick="location.href='#'">Drag</td>
 </tr>
</table>
<script>
forEach($("idMenu").getElementsByTagName("td"), function(x, i){
 var ct1 = new ColorTrans(x, { StartColor: "#666", EndColor: "#fff" });
 var ct2 = new ColorTrans(x, { StartColor: "#f6f6f6", EndColor: "rgb(20,150,0)", CssColor: "backgroundColor" });
 x.onmouseover = function(){ ct1.FadeIn(); ct2.FadeIn(); }
 x.onmouseout = function(){ ct1.FadeOut(); ct2.FadeOut(); }
})
</script>
<Br />
<Br />
<div id="idRandom" style="padding:10px;color:#fff; background-color:#CCC;">点击随机换颜色</div>
<script>
var ctRandom = new ColorTrans("idRandom", { EndColor: "#CCC", CssColor: "backgroundColor" })
$("idRandom").onclick = function(){
 var rgb = Map([1,1,1], function(){ return Math.floor((Math.random() * 255)); } );
 ctRandom.Reset({ StartColor: this.style.backgroundColor, EndColor: "rgb(" + rgb[0] + "," + rgb[1] + "," + rgb[2] + ")" })
 ctRandom.FadeIn();
}
</script>
</body>
</html>

PS：这里再为大家推荐几款本站的相关在线工具：

在线RGB、HEX颜色代码生成器：
http://tools.jb51.net/color/rgb_color_generator

RGB颜色查询对照表_颜色代码表_颜色的英文名称大全：
http://tools.jb51.net/color/jPicker

在线网页调色板工具：
http://tools.jb51.net/color/color_picker

在线颜色选择器工具/RGB颜色查询对照表：
http://tools.jb51.net/color/colorpicker

更多关于JavaScript相关内容可查看本站专题：《JavaScript切换特效与技巧总结》、《JavaScript查找算法技巧总结》、《JavaScript动画特效与技巧汇总》、《JavaScript错误与调试技巧总结》、《JavaScript数据结构与算法技巧总结》、《JavaScript遍历算法与技巧总结》及《JavaScript数学运算用法总结》

希望本文所述对大家JavaScript程序设计有所帮助。