Web/API/Element/underflow event

Non-standard This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

The non-standard underflow event, which is specific to Firefox, is fired when an element is no longer overflowed by its content. This only works for elements for which overflow is not set to visible.

The counterpart overflow event is fired when overflow occurs.

Bubbles	Yes
Cancelable	Yes
Interface	UIEvent
Event handler property	Unknown

Examples

<div id="wrapper">
    <div id="child"></div>
</div>
<br/>
<label><input type="checkbox" id="toggle" checked/> Overflow</label>

<style>
 #wrapper {
    width: 20px;
    height: 20px;
    background: #000;
    padding: 5px;
    overflow: hidden;
  }

  #child {
    width: 40px;
    height: 40px;
    border: 2px solid grey;
    background: #ccc;
  }
</style>

<script>
  var wrapper = document.getElementById("wrapper"),
      child = document.getElementById("child"),
      toggle = document.getElementById("toggle");

  wrapper.addEventListener("overflow", function( event ) {
      console.log( event );
  }, false);

  wrapper.addEventListener("underflow", function( event ) {
      console.log( event );
  }, false);

  toggle.addEventListener("change", function( event ) {
      if ( event.target.checked ) {
          child.style.width = "40px";
          child.style.height = "40px";
      } else {
          child.style.width = "10px";
          child.style.height = "10px";
      }
    
  }, false);
</script>

Specifications

Not part of any specification.

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
underflow event Non-standard'	Chrome No support No	Edge No support No	Firefox Full support Yes	IE No support No	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox Android Full support Yes	Opera Android No support No	Safari iOS No support No	Samsung Internet Android No support No

Legend

Full support  

Full support

No support  

No support

Non-standard. Expect poor cross-browser support.'

Non-standard. Expect poor cross-browser support.

See also

• Related events: overflow

Element: underflow event by Mozilla Contributors is licensed under CC-BY-SA 2.5.