interest-delay-start

Syntax

/* Keyword or custom delay */
interest-delay-start: normal;
interest-delay-start: 2s;
interest-delay-start: 250ms;

/* Global values */
interest-delay-start: inherit;
interest-delay-start: initial;
interest-delay-start: revert;
interest-delay-start: revert-layer;
interest-delay-start: unset;

Values

normal

Sets the delay to the browser's default delay. This is the initial value.

<time>

Sets the delay to a specific duration. The value must be positive, otherwise the property becomes invalid.

Formal definition

Formal syntax

interest-delay-start = 
  normal  |
  <time>  

Examples

Creating a basic interest-delay-start effect

In this example, we demonstrate how interest-delay-start affects interest invoker behavior.

HTML

The markup includes a <button>, a <p>, and an <input> of type checkbox. We specify the <button> as an interest invoker by giving it the interestfor attribute, whose value matches the id of the <p> element. This makes the paragraph the target element. The paragraph is turned into a popover by giving it the popover attribute, which hides it initially.

<button interestfor="mypopover">Button</button>
<p id="mypopover" popover>Hover tooltip</p>
<form>
  <input type="checkbox" id="apply-delay" />
  <label for="apply-delay">
    Apply an <code>interest-delay-start</code> of <code>2s</code>
  </label>
</form>

CSS

In the CSS, we specify a rule with a .delay selector that applies an interest-delay-start value of 2s to any interest invoker the delay class is set on. We will set this on the <button> when the checkbox is checked using JavaScript.

.delay {
  interest-delay-start: 2s;
}

JavaScript

In our script, we get references to the <button> and the checkbox, then create an event listener that toggles the delay class on the <button> whenever the checkbox value changes (when it is checked or unchecked).

const btn = document.querySelector("button");
const checkbox = document.querySelector("input");
checkbox.addEventListener("change", () => {
  btn.classList.toggle("delay");
});

Result

This renders as follows:

Try showing interest in the button (for example, by hovering or focusing it) and then losing interest to observe the popover showing and hiding. By default, the popover shows and hides after a very short delay.

Now check the checkbox and try the same actions again. This time, the popover should appear after a delay of 2s when interest is shown. The delay after interest is lost should be unaffected.

Removing interest-delay-start after interest has been shown

In this example, we show how to remove the interest-delay-start from multiple interest invoker elements after interest has been shown on one of them.

This is a useful technique. Having a popover appear as soon as interest is shown on any invoker would create a distracting and annoying user experience, which is why browsers add a small delay by default (see the interest-delay description for more details). However, once users have shown interest in an invoker, it is convenient to allow them to move between other invokers quickly without delay.

HTML

The markup includes three <button> elements wrapped in a paragraph with a container class, and another paragraph that has been turned into a popover using the popover attribute. All three buttons are set up as interest invokers and reference the popover as their target using the interestfor attribute.

<p class="container">
  <button interestfor="mypopover">Button 1</button>
  <button interestfor="mypopover">Button 2</button>
  <button interestfor="mypopover">Button 3</button>
</p>
<p id="mypopover" popover>Hover tooltip</p>

CSS

In the CSS, we apply an interest-delay-start value of 1s to the buttons, then position the popover below whatever button is having interest shown on it by giving it a position-area value of bottom (see Popover anchoring positioning for more information).

button {
  interest-delay-start: 1s;
}

#mypopover {
  position-area: bottom;
}

Finally, we combine the :interest-source pseudo-class with the :has() pseudo-class to apply interest-delay-start: 0s to all buttons inside the paragraph, but only when the paragraph contains a button on which interest has been shown (that is, matched by button:interest-source).

.container:has(button:interest-source) button {
  interest-delay-start: 0s;
}

Result

This renders as follows:

Try showing interest in any button and notice how, when you then immediately show interest in another button, the popover appears without delay. If you stop showing interest in the buttons and then start again, the initial delay will return.

Specifications

Browser compatibility

See also

• interest-delay-end, interest-delay
• Popover API
• Using interest invokers
• CSS basic user interface module