- document.querySelector(" "); 单个元素获取
- document.querySelectorAll(" "); 多个元素获取
1 <div class="box box1"></div> 2 <div class="box box2"></div> 3 <div class="box box3" id="box3"></div> 4 <div class="box box4"></div> 5 6 <script> 7 //H5中获取单个元素 document.querySelector 8 var box1 = document.querySelector(".box1"); 9 var box3 = document.querySelector("#box3"); 10 box1.style.backgroundColor = "red"; 11 box3.style.backgroundColor = "pink"; 12 13 //H5中获取多个元素(获取的是个数组) document.querySelectorAll 14 var boxArr = document.querySelectorAll(".box"); 15 boxArr[3].style.backgroundColor = "green"; 16 //for循环进行遍历操作 17 for(var i = 0;i<boxArr.length;i++){ 18 boxArr[i].innerText = i; 19 } 20 </script>
- 新增的类名操作:加、删、判断、切换
- 加:
box.classList.add("active");
- 删:
box.classList.remove("active");
- 判断:
box.classList.contains("active"); >>>>返回值是一个布尔值,true or false
- 切换:
box.classList.toggle("active");
<style> div{ width: 300px; height: 100px; margin: 10px auto; border: 1px solid #000; } .active { border-radius:50%; background-color: hotpink; } </style> <body> <button>box1的active类名切换</button> <div class="box box1"></div> <div class="box box2"></div> <div class="box box3"></div> <div class="box box4"></div> <script> var btn = document.querySelector("button"); var box1 = document.querySelector(".box1"); var box3 = document.querySelector(".box3"); var box4 = document.querySelector(".box4"); //H5中新增的操作类名方法 //添加类名: box3.classList.add("active"); box4.classList.add("active"); //删除类名 // box4.classList.remove("active") //判断是否有类名 var bol = box4.classList.contains("active"); console.log(bol); if( bol = false){ box4.classList.add("active"); } //类名切换 btn.onclick = function () { box1.classList.toggle("active"); } </script> </body>