js 输出css

document.getElementById('myElement').style.color = 'red';
document.getElementById('myElement').style.backgroundColor = 'blue';

const style = document.createElement('style');
style.type = 'text/css';
style.innerHTML = `
  #myElement {
    color: red;
    background-color: blue;
  }
`;
document.head.appendChild(style);

const styleSheet = document.styleSheets[0]; // 获取第一个样式表
styleSheet.insertRule('#myElement { color: red; background-color: blue; }', styleSheet.cssRules.length);

const css = `
  #myElement {
    color: red;
    background-color: blue;
  }
  .anotherClass {
    font-size: 16px;
  }
`;
const style = document.createElement('style');
style.type = 'text/css';
style.innerHTML = css;
document.head.appendChild(style);