我为RGB和十六进制颜色做了一个小的Javascript颜色类，这个类还包括RGB和十六进制验证函数。我将代码作为一个片段添加到这个答案中。

var colorClass = function() { this.validateRgb = function(color) { return typeof color === 'object' && color.length === 3 && Math.min.apply(null, color) >= 0 && Math.max.apply(null, color) <= 255; }; this.validateHex = function(color) { return color.match(/^\#?(([0-9a-f]{3}){1,2})$/i); }; this.hexToRgb = function(color) { var hex = color.replace(/^\#/, ''); var length = hex.length; return [ parseInt(length === 6 ? hex['0'] + hex['1'] : hex['0'] + hex['0'], 16), parseInt(length === 6 ? hex['2'] + hex['3'] : hex['1'] + hex['1'], 16), parseInt(length === 6 ? hex['4'] + hex['5'] : hex['2'] + hex['2'], 16) ]; }; this.rgbToHex = function(color) { return '#' + ('0' + parseInt(color['0'], 10).toString(16)).slice(-2) + ('0' + parseInt(color['1'], 10).toString(16)).slice(-2) + ('0' + parseInt(color['2'], 10).toString(16)).slice(-2); }; }; var colors = new colorClass(); console.log(colors.hexToRgb('#FFFFFF'));// [255, 255, 255] console.log(colors.rgbToHex([255, 255, 255]));// #FFFFFF

我意识到这个问题有很多答案，但如果你像我一样，你知道你的HEX总是6个字符，带或不带#前缀，那么如果你想做一些快速内联的东西，这可能是最简单的方法。它不关心是否以散列开始。

var hex = "#ffffff";
var rgb = [
    parseInt(hex.substr(-6,2),16),
    parseInt(hex.substr(-4,2),16),
    parseInt(hex.substr(-2),16)
];

我假设您指的是html风格的十六进制符号，即#rrggbb。你的代码几乎是正确的，只是顺序颠倒了。它应该是:

var decColor = red * 65536 + green * 256 + blue;

此外，使用位移位可能会让它更容易阅读:

var decColor = (red << 16) + (green << 8) + blue;

我需要一个函数，接受无效值太像

Rgb (- 255,255,255) Rgb (510, 255, 255)

这是@cwolves answer的衍生

function rgb(r, g, b) {
  this.c = this.c || function (n) {
    return Math.max(Math.min(n, 255), 0)
  };

  return ((1 << 24) + (this.c(r) << 16) + (this.c(g) << 8) + this.c(b)).toString(16).slice(1).toUpperCase();
}

My example =) color: { toHex: function(num){ var str = num.toString(16); return (str.length<6?'#00'+str:'#'+str); }, toNum: function(hex){ return parseInt(hex.replace('#',''), 16); }, rgbToHex: function(color) { color = color.replace(/\s/g,""); var aRGB = color.match(/^rgb\((\d{1,3}[%]?),(\d{1,3}[%]?),(\d{1,3}[%]?)\)$/i); if(aRGB) { color = ''; for (var i=1; i<=3; i++) color += Math.round((aRGB[i][aRGB[i].length-1]=="%"?2.55:1)*parseInt(aRGB[i])).toString(16).replace(/^(.)$/,'0$1'); } else color = color.replace(/^#?([\da-f])([\da-f])([\da-f])$/i, '$1$1$2$2$3$3'); return '#'+color; }

哇。这些答案都不能处理分数的边缘情况，等等。当r, g, b为零时，位移版本也不起作用。

这是一个可以处理r g b是小数的版本。它对颜色之间的插值很有用，所以我也包括了这段代码。但它仍然不能处理r, g, b在0-255范围之外的情况

/**
 * Operates with colors.
 * @class Q.Colors
 */
 Q.Color = {
    /**
     * Get a color somewhere between startColor and endColor
     * @method toHex
     * @static
     * @param {String|Number} startColor 
     * @param {String|Number} endColor 
     * @param {String|Number} fraction 
     * @returns {String} a color as a hex string without '#' in front
     */
    toHex: function (r, g, b) {
        return [r, g, b].map(x => {
            const hex = Math.round(x).toString(16)
            return hex.length === 1 ? '0' + hex : hex
          }).join('');
    },
    /**
     * Get a color somewhere between startColor and endColor
     * @method between
     * @static
     * @param {String|Number} startColor 
     * @param {String|Number} endColor 
     * @param {String|Number} fraction 
     * @returns {String} a color as a hex string without '#' in front
     */
    between: function(startColor, endColor, fraction) {
        if (typeof startColor === 'string') {
            startColor = parseInt(startColor.replace('#', '0x'), 16);
        }
        if (typeof endColor === 'string') {
            endColor = parseInt(endColor.replace('#', '0x'), 16);
        }
        var startRed = (startColor >> 16) & 0xFF;
        var startGreen = (startColor >> 8) & 0xFF;
        var startBlue = startColor & 0xFF;
        var endRed = (endColor >> 16) & 0xFF;
        var endGreen = (endColor >> 8) & 0xFF;
        var endBlue = endColor & 0xFF;
        var newRed = startRed + fraction * (endRed - startRed);
        var newGreen = startGreen + fraction * (endGreen - startGreen);
        var newBlue = startBlue + fraction * (endBlue - startBlue);
        return Q.Color.toHex(newRed, newGreen, newBlue);
    },
    /**
     * Sets a new theme-color on the window
     * @method setWindowTheme
     * @static
     * @param {String} color in any CSS format, such as "#aabbcc"
     * @return {String} the previous color
     */
    setWindowTheme: function (color) {
        var meta = document.querySelector('meta[name="theme-color"]');
        var prevColor = null;
        if (meta) {
            prevColor = meta.getAttribute('content');
        }
        if (color) {
            if (!meta) {
                meta = document.createElement('meta');
                meta.setAttribute('name', 'theme-color');
            }
            meta.setAttribute('content', color);
        }
        return prevColor;
    },
    /**
     * Gets the current window theme color
     * @method getWindowTheme
     * @static
     * @param {String} color in any CSS format, such as "#aabbcc"
     * @return {String} the previous color
     */
    getWindowTheme: function () {
        var meta = document.querySelector('meta[name="theme-color"]');
        return meta.getAttribute('content');
    }
}