'#'+Math.random().toString(16).slice(-3) // three-numbers format aka #f3c
'#'+Math.random().toString(16).slice(-6) // six-number format aka #abc123

Paul Irish写的文章《JavaScript中的随机十六进制颜色代码生成器》绝对令人惊叹。使用:

'#' + Math.floor(Math.random()*16777215).toString(16).padStart(6, '0');

感谢Haytam分享padStart来解决十六进制代码长度的问题。

我想要材质-颜色ui。这个答案是stackoverflow

和这个github repo defaultPalette()，我做了这个javascript，你可以导入到，你可以通过const color= defaultPalette()调用它;or const color = defaultPalette('flatui');

    <!-- language: lang-js -->   
    const defaultPalette = {
    // Red, Pink, Purple, Deep Purple, Indigo, Blue, Light Blue, Cyan, Teal, Green, Light Green, Lime, Yellow, Amber, Orange, Deep Orange, Brown, Grey, Blue Grey
    '50': ['#FFEBEE', '#FCE4EC', '#F3E5F5', '#EDE7F6', '#E8EAF6', '#E3F2FD', '#E1F5FE', '#E0F7FA', '#E0F2F1', '#E8F5E9', '#F1F8E9', '#F9FBE7', '#FFFDE7', '#FFF8E1', '#FFF3E0', '#FBE9E7', '#EFEBE9', '#FAFAFA', '#ECEFF1'],
    '100': ['#FFCDD2', '#F8BBD0', '#E1BEE7', '#D1C4E9', '#C5CAE9', '#BBDEFB', '#B3E5FC', '#B2EBF2', '#B2DFDB', '#C8E6C9', '#DCEDC8', '#F0F4C3', '#FFF9C4', '#FFECB3', '#FFE0B2', '#FFCCBC', '#D7CCC8', '#F5F5F5', '#CFD8DC'],
    '200': ['#EF9A9A', '#F48FB1', '#CE93D8', '#B39DDB', '#9FA8DA', '#90CAF9', '#81D4FA', '#80DEEA', '#80CBC4', '#A5D6A7', '#C5E1A5', '#E6EE9C', '#FFF59D', '#FFE082', '#FFCC80', '#FFAB91', '#BCAAA4', '#EEEEEE', '#B0BEC5'],
    '300': ['#E57373', '#F06292', '#BA68C8', '#9575CD', '#7986CB', '#64B5F6', '#4FC3F7', '#4DD0E1', '#4DB6AC', '#81C784', '#AED581', '#DCE775', '#FFF176', '#FFD54F', '#FFB74D', '#FF8A65', '#A1887F', '#E0E0E0', '#90A4AE'],
    '400': ['#EF5350', '#EC407A', '#AB47BC', '#7E57C2', '#5C6BC0', '#42A5F5', '#29B6F6', '#26C6DA', '#26A69A', '#66BB6A', '#9CCC65', '#D4E157', '#FFEE58', '#FFCA28', '#FFA726', '#FF7043', '#8D6E63', '#BDBDBD', '#78909C'],
    '500': ['#F44336', '#E91E63', '#9C27B0', '#673AB7', '#3F51B5', '#2196F3', '#03A9F4', '#00BCD4', '#009688', '#4CAF50', '#8BC34A', '#CDDC39', '#FFEB3B', '#FFC107', '#FF9800', '#FF5722', '#795548', '#9E9E9E', '#607D8B'],
    '600': ['#E53935', '#D81B60', '#8E24AA', '#5E35B1', '#3949AB', '#1E88E5', '#039BE5', '#00ACC1', '#00897B', '#43A047', '#7CB342', '#C0CA33', '#FDD835', '#FFB300', '#FB8C00', '#F4511E', '#6D4C41', '#757575', '#546E7A'],
    '700': ['#D32F2F', '#C2185B', '#7B1FA2', '#512DA8', '#303F9F', '#1976D2', '#0288D1', '#0097A7', '#00796B', '#388E3C', '#689F38', '#AFB42B', '#FBC02D', '#FFA000', '#F57C00', '#E64A19', '#5D4037', '#616161', '#455A64'],
    '800': ['#C62828', '#AD1457', '#6A1B9A', '#4527A0', '#283593', '#1565C0', '#0277BD', '#00838F', '#00695C', '#2E7D32', '#558B2F', '#9E9D24', '#F9A825', '#FF8F00', '#EF6C00', '#D84315', '#4E342E', '#424242', '#37474F'],
    '900': ['#B71C1C', '#880E4F', '#4A148C', '#311B92', '#1A237E', '#0D47A1', '#01579B', '#006064', '#004D40', '#1B5E20', '#33691E', '#827717', '#F57F17', '#FF6F00', '#E65100', '#BF360C', '#3E2723', '#212121', '#263238'],
    'A100': ['#FF8A80', '#FF80AB', '#EA80FC', '#B388FF', '#8C9EFF', '#82B1FF', '#80D8FF', '#84FFFF', '#A7FFEB', '#B9F6CA', '#CCFF90', '#F4FF81', '#FFFF8D', '#FFE57F', '#FFD180', '#FF9E80'],
    'A200': ['#FF5252', '#FF4081', '#E040FB', '#7C4DFF', '#536DFE', '#448AFF', '#40C4FF', '#18FFFF', '#64FFDA', '#69F0AE', '#B2FF59', '#EEFF41', '#FFFF00', '#FFD740', '#FFAB40', '#FF6E40'],
    'A400': ['#FF1744', '#F50057', '#D500F9', '#651FFF', '#3D5AFE', '#2979FF', '#00B0FF', '#00E5FF', '#1DE9B6', '#00E676', '#76FF03', '#C6FF00', '#FFEA00', '#FFC400', '#FF9100', '#FF3D00'],
    'A700': ['#D50000', '#C51162', '#AA00FF', '#6200EA', '#304FFE', '#2962FF', '#0091EA', '#00B8D4', '#00BFA5', '#00C853', '#64DD17', '#AEEA00', '#FFD600', '#FFAB00', '#FF6D00', '#DD2C00'],
    'flatui': ['#1ABC9C', '#2ECC71', '#3498DB', '#9B59B6', '#34495E', '#16A085', '#27AE60', '#2980B9', '#8E44AD', '#2C3E50', '#F1C40F', '#E67E22', '#E74C3C', '#ECF0F1', '#95A5A6', '#F39C12', '#D35400', '#C0392B', '#BDC3C7', '#7F8C8D'],
    'metro': ['#A4C400', '#60A917', '#008A00', '#00ABA9', '#1BA1E2', '#0050EF', '#6A00FF', '#AA00FF', '#F472D0', '#D80073', '#A20025', '#E51400', '#FA6800', '#F0A30A', '#E3C800', '#825A2C', '#6D8764', '#647687', '#76608A', '#A0522D']
}
const defaultBase = ['50', '100', '200', '300', '400', '500', '600', '700', '800', '900', 'A100', 'A200', 'A400', 'A700', 'flatui', 'metro']

const randomIntFromInterval = (min, max) => { // min and max included
    return Math.floor(Math.random() * (max - min + 1) + min)
}


export default (choosePalette)=>{
    if (choosePalette === undefined) {
        const nrindexdefault = defaultBase.length - 1;
        const number = randomIntFromInterval(0, nrindexdefault);

        const defaultPaletteColorsArray = defaultPalette[defaultBase[number]];
        const nrindexcolor = defaultPaletteColorsArray.length - 1;
        const defaultColor = randomIntFromInterval(0, nrindexcolor)
        return defaultPaletteColorsArray[defaultColor];
    } else {
        const defaultPaletteColorsArray = defaultPalette[choosePalette];
        const nrindexcolor = defaultPaletteColorsArray.length - 1;
        const defaultColor = randomIntFromInterval(0, nrindexcolor)
        return defaultPaletteColorsArray[defaultColor];
    }

}

我喜欢这个:'#' + (Math.random().toString(16) + "000000").substring(2,8)

谁能打败它?

'#' + Math.random().toString(16).substr(-6);

它保证一直工作:http://jsbin.com/OjELIfo/2/edit

根据eterps的注释，如果随机颜色的十六进制表示非常短(0.730224609375 => 0.baf)，上面的代码仍然可以生成更短的字符串。

这段代码应该在所有情况下工作:

function makeRandomColor(){
  var c = '';
  while (c.length < 7) {
    c += (Math.random()).toString(16).substr(-6).substr(-1)
  }
  return '#' + c;
}

Use:

function random_color(format)
{
    var rint = Math.round(0xffffff * Math.random());
    switch(format)
    {
        case 'hex':
            return ('#0' + rint.toString(16)).replace(/^#0([0-9a-f]{6})$/i, '#$1');
            break;

        case 'rgb':
            return 'rgb(' + (rint >> 16) + ',' + (rint >> 8 & 255) + ',' + (rint & 255) + ')';
            break;

        default:
            return rint;
            break;
    }
}

升级版:

function random_color( format ){
  var rint = Math.floor( 0x100000000 * Math.random());
  switch( format ){
    case 'hex':
      return '#' + ('00000'   + rint.toString(16)).slice(-6).toUpperCase();
    case 'hexa':
      return '#' + ('0000000' + rint.toString(16)).slice(-8).toUpperCase();
    case 'rgb':
      return 'rgb('  + (rint & 255) + ',' + (rint >> 8 & 255) + ',' + (rint >> 16 & 255) + ')';
    case 'rgba':
      return 'rgba(' + (rint & 255) + ',' + (rint >> 8 & 255) + ',' + (rint >> 16 & 255) + ',' + (rint >> 24 & 255)/255 + ')';
    default:
      return rint;
  }
}