Element: securitypolicyviolation event

The securitypolicyviolation event is fired when a Content Security Policy is violated.

Bubbles Yes
Cancelable No
Interface SecurityPolicyViolationEvent
Event handler property onsecuritypolicyviolation

The event is fired on the element that violates the policy and bubbles. It is normally handled by an event handler on the Window or Document object.

The handler can be assigned using the GlobalEventHandlers.onsecuritypolicyviolation property or using EventTarget.addEventListener().

Note: You must add the handler for this event to a top level object (i.e. Window or Document). While the property exists in HTML elements, you can't assign a handler to the property until the elements have been loaded, by which time this event will already have fired.


The code below shows how you might add an event handler function using the onsecuritypolicyviolation global event handler property or addEventListener() on the top level Window (you could use exactly the same approach on Document).

window.onsecuritypolicyviolation = function(e) {
   // Handle SecurityPolicyViolationEvent e here

window.addEventListener("securitypolicyviolation", (e) => {
  // Handle SecurityPolicyViolationEvent e here


HTML Standard
# event-securitypolicyviolation

Browser compatibility

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See also