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HTML

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Insecure Resource

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CSS

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JavaScript

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Babel includes JSX processing.

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HTML 

              
                <!--https://www.niemvuilaptrinh.com/-->
<button class="nut-mo-chatbox" onclick="moForm()">Chat</button>
<div class="Chatbox" id="myForm">
  <form action="" class="form-container">
    <h1>Chatbox</h1>

    <label for="msg"><b>Lời Nhắn</b></label>
    <textarea placeholder="Bạn hãy nhập lời nhắn.." name="msg" required></textarea>

    <button type="submit" class="btn">Gửi</button>
    <button type="button" class="btn nut-dong-chatbox" onclick="dongForm()">Đóng</button>
  </form>
</div>
!

CSS 

              
                {box-sizing: border-box;}

/* Nút Để Mở Chatbox */
.nut-mo-chatbox {
  background-color: #555;
  color: white;
  padding: 16px 20px;
  border: none;
  cursor: pointer;
  opacity: 0.8;
  position: fixed;
  bottom: 23px;
  right: 28px;
  width: 280px;
}

/* Ẩn chatbox mặc định */
.Chatbox {
  display: none;
  position: fixed;
  bottom: 0;
  right: 15px;
  border: 3px solid #f1f1f1;
  z-index: 9;
}

/* Thêm style cho form */
.form-container {
  max-width: 300px;
  padding: 10px;
  background-color: white;
}

/* thiết lập style textarea */
.form-container textarea {
  width: 100%;
  padding: 5px;
  margin: 5px 0 22px 0;
  border: none;
  background: #f1f1f1;
  resize: none;
  min-height: 100px;
}

/*thiết lập style cho textarea khi được focus */
.form-container textarea:focus {
  background-color: #ddd;
  outline: none;
}

/* Sthiết lập style cho nút trong form*/
.form-container .btn {
  background-color: #4CAF50;
  color: white;
  padding: 16px 20px;
  border: none;
  cursor: pointer;
  width: 100%;
  margin-bottom:10px;
  opacity: 0.8;
}

/* Thiết lập màu nền cho nút đóng chatbox */
.form-container .nut-dong-chatbox {
  background-color: red;
}

/* Thêm hiệu ứng hover cho nút*/
.form-container .btn:hover, .nut-mo-chatbox:hover {
  opacity: 1;
}
!

JS 

              
                /*Hàm Mở Form*/
function moForm() {
  document.getElementById("myForm").style.display = "block";
}
/*Hàm Đóng Form*/
function dongForm() {
  document.getElementById("myForm").style.display = "none";
}
!
999px

Console