<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Document</title></head><style> div{ width: 300px; height: 200px; background-color: red; transition: all 500ms ease; } .tall{ height: 300px; transition: all 500ms ease; }</style><body> <div> </div> <input type="button" value="展开" onclick="clikc()"></body></html><script> var div=document.querySelector('div'); var inp=document.querySelector('input'); let isclick=false;function clikc(){ isclick=!isclick; div.classList.toggle('tall'); isclick?inp.value="收起":inp.value="展开";}</script>
