強制回應是橫幅通知的替代方案。由於互動視窗會顯示在現有網頁內容的上方，因此顯示這類視窗時，不會造成版面配置位移。這個互動視窗會根據內容而放大。
HTML
<div id="modal" class="modal">
<button id="close-button" class="close-button" aria-label="close" tabindex="0">✕</button>
<div>
<h1>Notice</h1>
Lorem ipsum dolor sit amet.
</div>
</div>CSS
body {
overscroll-behavior-y: none;
font-family: system-ui;
padding: 2em;
background-color: #f4f4f4;
}
.modal {
position: fixed;
top: 50%;
left: 50%;
min-width: 66%;
transform: translate(-50%, -50%);
padding: 1em 2em 2em 2em;
background-color: white;
box-shadow: 0 0 15px rgba(0,0,0,0.2);
}
.close-button {
background: transparent;
border: none;
padding: 1em;
font-size: 1em;
position: absolute;
right: 0;
top: 0;
cursor: pointer;
}
JS
document.getElementById("close-button").onclick = () => {
document.getElementById("modal").style.display = "none";
}