js修改div的宽度和高度

// 获取div元素
var div = document.getElementById('myDiv');

// 修改宽度和高度
div.style.width = '200px';  // 设置宽度为200像素
div.style.height = '100px'; // 设置高度为100像素

var div = document.getElementById('myDiv');
div.setAttribute('style', 'width: 200px; height: 100px;');

/* CSS */
.my-custom-style {
    width: 200px;
    height: 100px;
}

// JavaScript
var div = document.getElementById('myDiv');
div.classList.add('my-custom-style');

var div = document.getElementById('myDiv');
console.log('Width:', div.clientWidth);
console.log('Height:', div.clientHeight);

var div = document.getElementById('myDiv');
console.log('Offset Width:', div.offsetWidth);
console.log('Offset Height:', div.offsetHeight);