Document: beforescriptexecute 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 beforescriptexecute event fires when a static <script> is about to start executing. It does not fire if the element is added dynamically, such as with appendChild().


Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("beforescriptexecute", (event) => {});

onbeforescriptexecute = (event) => {};

Event type

A generic Event.


function starting(e) {
  logMessage(`Starting script with ID: ${}`);

document.addEventListener("beforescriptexecute", starting, true);
// or
document.onbeforescriptexecute = starting;

View Live Example


Not part of any specification.

Browser compatibility

BCD tables only load in the browser

See also