获取DOM元素的方式

一、HTML中获取DOM元素

1.通过querySelector是静态获取的，而是用getElementsByClassName是动态获取，也就是说每一次使用都会去对dom节点调用一次

<div id="app">
<ul class="ul">
		<li>你好</li>
		<li>你好</li>
		<li>你好</li>
	</ul>
</div>
<script>
	let app = document.getElementById('app')
	let ul = document.getElementsByClassName('ul')
	let ul1 = document.querySelector('.ul')
	console.log(app);
	console.log(ul[0]);
	let lis = document.querySelectorAll('.ul li')
	console.log(lis.length);
	
	for(let i=0; i< lis.length;i++){
      
      
		console.log(ul1);
		ul1.appendChild(document.createElement('li'))
	}
	console.log(ul[0].innerHTML);
</script>

一、Vue中获取DOM元素

<div ref="app"><div>
<script>
// 获取DOM元素
this.$refs.app.$el.style.top = 0
this.$refs.app.$el.style.position = 'fixed'
this.$refs.app.$el.getBoundingClientRect()
</script>

二. uni-app中获取DOM元素

<view class="app"></view>
<script>
const query = uni.createSelectorQuery().in(this)
uni.createSelectorQuery().select('.app').fields({
      
      
		node: true,
		size: true
	})
	.exec(function(res) {
      
      
		console.log(res);
	})
</script>