Window: error event

The error event is fired on a Window object when a resource failed to load or couldn't be used — for example if a script has an execution error.

The event object is a UIEvent instance if it was generated from a user interface element, or an Event instance otherwise.

Examples

Live example

HTML

<div class="controls">
  <button id="script-error" type="button">Generate script error</button>
  <img class="bad-img" />
</div>

<div class="event-log">
  <label>Event log:</label>
  <textarea readonly class="event-log-contents" rows="8" cols="30"></textarea>
</div>

body {
  display: grid;
  grid-template-areas: "control  log";
}

.controls {
  grid-area: control;
  display: flex;
  align-items: center;
  justify-content: center;
}

.event-log {
  grid-area: log;
}

.event-log-contents {
  resize: none;
}

label, button {
  display: block;
}

button {
  height: 2rem;
  margin: .5rem;
}

img {
  width: 0;
  height: 0;
}

JS

const log = document.querySelector('.event-log-contents');

window.addEventListener('error', (event) => {
    log.textContent = log.textContent + `${event.type}: ${event.message}\n`;
    console.log(event)
});

const scriptError = document.querySelector('#script-error');
scriptError.addEventListener('click', () => {
    const badCode = 'const s;';
    eval(badCode);
});

Result

Specifications

Browser compatibility

See also

• This event on Element targets: error event