我给洛达什做了这个。它将一个RGB字符串，如“30,209,19”转换为其对应的十六进制字符串“#1ed113”:

var rgb = '30,209,19';

var hex = _.reduce(rgb.split(','), function(hexAccumulator, rgbValue) {
    var intColor = _.parseInt(rgbValue);

    if (_.isNaN(intColor)) {
        throw new Error('The value ' + rgbValue + ' was not able to be converted to int');
    }

    // Ensure a value such as 2 is converted to "02".
    var hexColor = _.padLeft(intColor.toString(16), 2, '0');

    return hexAccumulator + hexColor;
}, '#');

虽然这个答案不太可能完全符合问题，但它可能非常有用。

创建任意随机元素

var toRgb = document.createElement（'div'）;

将任何有效的样式设置为要转换的颜色

toRg.style.颜色=“hsl(120、60%、70%)”;

再次调用style属性

> toRgb.style.color;

< "rgb(133,225,133)"您的颜色已转换为Rgb

适用于:Hsl，海克斯

不适用于:命名颜色

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;

下面是将HEX颜色值分别更改为红色，绿色，蓝色的Javascript代码。

R = hexToR("#FFFFFF");
G = hexToG("#FFFFFF");
B = hexToB("#FFFFFF");

function hexToR(h) {return parseInt((cutHex(h)).substring(0,2),16)}
function hexToG(h) {return parseInt((cutHex(h)).substring(2,4),16)}
function hexToB(h) {return parseInt((cutHex(h)).substring(4,6),16)}
function cutHex(h) {return (h.charAt(0)=="#") ? h.substring(1,7):h}

建立了我自己的十六进制RGB转换器。我希望这能帮助到一些人。

我用react来做沙盒。

用法:

根据官方文档安装React，或者如果你全局安装了npx，运行npx create-react-app hexto -rgb

import React, { Component, Fragment } from 'react';
const styles = {
  display: 'block',
  margin: '20px auto',
  input: {
    width: 170,
  },
  button: {
    margin: '0 auto'
  }
}

//  test case 1
//    #f0f
//  test case 2
//    #ff00ff

class HexToRGBColorConverter extends Component {

  state = {
    result: false,
    color: "#ff00ff",
  }
  
  hexToRgb = color => {    
    let container = [[], [], []];
    // check for shorthand hax string
    if (color.length >= 3) {
      // remove hash from string
      // convert string to array
      color = color.substring(1).split("");
      for (let key = 0; key < color.length; key++) {        
        let value = color[key];
        container[2].push(value);
        // if the length is 3 we 
        // we need to add the value 
        // to the index we just updated
        if (color.length === 3) container[2][key] += value;
      }
      
      for (let index = 0; index < color.length; index++) {
        let isEven = index % 2 === 0;
        // If index is odd an number 
        // push the value into the first
        // index in our container
        if (isEven) container[0].push(color[index]);
        // If index is even an number 
        if (!isEven) {
          // again, push the value into the
          // first index in the container
          container[0] += color[index];
          // Push the containers first index
          // into the second index of the container
          container[1].push(container[0]);
          // Flush the first index of
          // of the container 
          // before starting a new set
          container[0] = [];
        }
      }
      // Check container length
      if (container.length === 3) {
        // Remove only one element of the array
        // Starting at the array's first index
        container.splice(0, 1);
        let values = container[color.length % 2];
        return {
          r: parseInt(values[0], 16),
          g: parseInt(values[1], 16),
          b: parseInt(values[2], 16)
        }
      }
    }
    return false;
  }  

  handleOnClick = event => {
    event.preventDefault();
    const { color } = this.state;
    const state = Object.assign({}, this.state);
    state.result = this.hexToRgb(color);
    this.setState(state);
  }

  handleOnChange = event => {
    event.preventDefault();
    const { value } = event.currentTarget;
    const pattern = /^([a-zA-Z0-9])/;
    const boundaries = [3, 6];
    if (
      pattern.test(value) &&
      boundaries.includes(value.length)
    ) {
      const state = Object.assign({}, this.state);
      state.color = `#${value}`;
      this.setState(state);
    }
  }

  render() {
    const { color, result } = this.state;
    console.log('this.state ', color, result);

    return (
      <Fragment>
        <input 
          type="text" 
          onChange={this.handleOnChange} 
          style={{ ...styles, ...styles.input }} />
        <button 
          onClick={this.handleOnClick}
          style={{ ...styles, ...styles.button }}>
          Convert hex to rgba
        </button>
        { 
          !!result && 
          <div style={{ textAlign: 'center' }}>
            Converted { color } to { JSON.stringify(result) }
          </div> 
        }
      </Fragment>
    )
  }
}
export default App;

快乐编码=)

function hex2rgb(hex) {
  return ['0x' + hex[1] + hex[2] | 0, '0x' + hex[3] + hex[4] | 0, '0x' + hex[5] + hex[6] | 0];
}