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嵌套的ol必须写在li里边吗
我百度搜了一下,说是必须写在li里边。但是
我写成底下这样,在chrome浏览器也能正常显示,这有什么说法吗?
<ol> <li>尚學堂</li> <ol> <li>阿里</li> <li>京東</li> </ol> <li>百戰程序員</li> </ol>
复制文档中的代码粘贴上去,idea显示NBSP,vscode里有黄色的方块,怎么解决
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Document</title> <script> var a = document.getElementsByTagName("div")[1] console.log(a) </script> </head> <body> <div> Hello Word!</div> <div> 2 </div> </body> </html>
我的怎么出undefined
before() 方法在同级前面插入元素
刚测试了在有多个同级元素时,会在每一个同级元素前添加新元素,
这种情况需要用添加属性解决嘛
<body> <div class="box" id="box"></div> <script> var box = document.getElementById("box"); box.setAttribute("style","width: 200px;height: 200px;background: aqua;") // box.style.height = "300px"; // box.style.width = "300px"; // box.style.backgroundColor = "red"; // box.style.cssText = "width: 200px;height: 200px;background: aquamarine;" </script> </body> 老师,这些代码我都明白,但是我想不明白为什么要用js去实现样式呢 一开始学的在头部里<style>标签里去设计不好吗?
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Document</title> </head> <style> #someDiv{ width: 300px; height: 300px; background-color: aqua; opacity: 1; } </style> <body> <div id="someDiv"></div> <script> var div =document.getElementById("somerDiv"); var opacity =1; var fade =setInterval(function(){ opacity-=0.05; if(opacity >0){ div.style.opacity=opacity; }else{ clearInterval(fade) } },60) </script> </body> </html>
运行不了