Chèn embed youtube hoặc iframe với responsive

Các bạn làm theo hướng dẫn bên dưới

Code CSS:

.iframe-container{
  position: relative;
  width: 100%;
  padding-bottom: 56.25%; 
  height: 0;
}
.iframe-container iframe{
  position: absolute;
  top:0;
  left: 0;
  width: 100%;
  height: 100%;
}

Ví dụ:

 <style>
 .iframe-container{
  position: relative;
  width: 100%;
  padding-bottom: 56.25%; 
  height: 0;
}
.iframe-container iframe{
  position: absolute;
  top:0;
  left: 0;
  width: 100%;
  height: 100%;
}
 </style>
<div class="iframe-container"><iframe class="" width="560" height="315" src="https://www.youtube.com/embed/9YffrCViTVk" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe></div>