Htmx provides an extensive events system that can be used to modify and enhance behavior. Events are listed below.
htmx:abortThis event is different than other events: htmx does not trigger it, but rather listens for it.
If you send an htmx:abort event to an element making a request, it will abort the request:
<button id="request-button" hx-post="/example">Issue Request</button>
<button onclick="htmx.trigger('#request-button', 'htmx:abort')">Cancel Request</button>
htmx:afterOnLoadThis event is triggered after an AJAX onload has finished. Note that this does not mean that the content
has been swapped or settled yet, only that the request has finished.
detail.elt - the element that dispatched the request or if the body no longer contains the element then the closest parentdetail.xhr - the XMLHttpRequestdetail.target - the target of the requestdetail.requestConfig - the configuration of the AJAX requesthtmx:afterProcessNodeThis event is triggered after htmx has initialized a DOM node. It can be useful for extensions to build additional features onto a node.
detail.elt - the element being initializedhtmx:afterRequestThis event is triggered after an AJAX request has finished either in the case of a successful request (although
one that may have returned a remote error code such as a 404) or in a network error situation. This event
can be paired with htmx:beforeRequest to wrap behavior around a request cycle.
detail.elt - the element that dispatched the request or if the body no longer contains the element then the closest parentdetail.xhr - the XMLHttpRequestdetail.target - the target of the requestdetail.requestConfig - the configuration of the AJAX requestdetail.successful - true if the response has a 20x status code or is marked detail.isError = false in the
htmx:beforeSwap event, else falsedetail.failed - true if the response does not have a 20x status code or is marked detail.isError = true in the
htmx:beforeSwap event, else falsehtmx:afterSettleThis event is triggered after the DOM has settled.
detail.elt - the updated elementdetail.xhr - the XMLHttpRequestdetail.target - the target of the requestdetail.requestConfig - the configuration of the AJAX requesthtmx:afterSwapThis event is triggered after new content has been swapped into the DOM.
detail.elt - the swapped in elementdetail.xhr - the XMLHttpRequestdetail.target - the target of the requestdetail.requestConfig - the configuration of the AJAX requesthtmx:beforeCleanupElementThis event is triggered before htmx disables an element or removes it from the DOM.
detail.elt - the element to be cleaned uphtmx:beforeOnLoadThis event is triggered before any response processing occurs. If you call preventDefault() on the event to cancel it, no swap will occur.
detail.elt - the element that dispatched the requestdetail.xhr - the XMLHttpRequestdetail.target - the target of the requestdetail.requestConfig - the configuration of the AJAX requesthtmx:beforeProcessNodeThis event is triggered before htmx initializes a DOM node and has processed all of its hx- attributes. This gives extensions and other external code the ability to modify the contents of a DOM node before it is processed.
detail.elt - the element being initializedhtmx:beforeRequestThis event is triggered before an AJAX request is issued. If you call preventDefault() on the event to cancel it, no request will occur.
detail.elt - the element that dispatched the requestdetail.xhr - the XMLHttpRequestdetail.target - the target of the requestdetail.requestConfig - the configuration of the AJAX requesthtmx:beforeSendThis event is triggered right before a request is sent. You may not cancel the request with this event.
detail.elt - the element that dispatched the requestdetail.xhr - the XMLHttpRequestdetail.target - the target of the requestdetail.requestConfig - the configuration of the AJAX requesthtmx:beforeSwapThis event is triggered before any new content has been swapped into the DOM.
Most values on detail can be set to override subsequent behavior, other than where response headers take precedence.
If you call preventDefault() on the event to cancel it, no swap will occur.
You can modify the default swap behavior by modifying the shouldSwap, selectOverride, swapOverride and target properties of the event detail.
See the documentation on configuring swapping for more details.
detail.elt - the target of the swapdetail.xhr - the XMLHttpRequestdetail.requestConfig - the configuration of the AJAX requestdetail.requestConfig.elt - the element that dispatched the requestdetail.shouldSwap - if the content will be swapped (defaults to false for non-200 response codes)detail.ignoreTitle - if true any title tag in the response will be ignoreddetail.isError - whether error events should be triggered and also determines the values of detail.successful and detail.failed in later eventsdetail.serverResponse - the server response as text to be used for the swapdetail.selectOverride - add this to use instead of an hx-select valuedetail.swapOverride - add this to use instead of an hx-swap valuedetail.target - the target of the swaphtmx:beforeTransitionThis event is triggered before a View Transition
wrapped swap occurs. If you call preventDefault() on the event to cancel it, the View Transition will not occur and the normal swapping logic will
happen instead.
detail.elt - the element that dispatched the requestdetail.xhr - the XMLHttpRequestdetail.requestConfig - the configuration of the AJAX requestdetail.shouldSwap - if the content will be swapped (defaults to false for non-200 response codes)detail.target - the target of the swaphtmx:configRequestThis event is triggered after htmx has collected parameters for inclusion in the request. It can be used to include or update the parameters that htmx will send:
document.body.addEventListener('htmx:configRequest', function(evt) {
evt.detail.parameters['auth_token'] = getAuthToken(); // add a new parameter into the mix
});
Note that if an input value appears more than once the value in the parameters object will be an array, rather
than a single value.
detail.parameters - the parameters that will be submitted in the requestdetail.unfilteredParameters - the parameters that were found before filtering by hx-paramsdetail.headers - the request headersdetail.elt - the element that triggered the requestdetail.target - the target of the requestdetail.verb - the HTTP verb in usehtmx:confirmThis event is fired on every trigger for a request (not just on elements that have a hx-confirm attribute).
It allows you to cancel (or delay) issuing the AJAX request.
If you call preventDefault() on the event, it will not issue the given request.
The detail object contains a function, evt.detail.issueRequest(skipConfirmation=false), that can be used to issue the actual AJAX request at a later point.
Combining these two features allows you to create an asynchronous confirmation dialog.
Here is a basic example that shows the basic usage of the htmx:confirm event without altering the default behavior:
document.body.addEventListener('htmx:confirm', function(evt) {
// 0. To modify the behavior only for elements with the hx-confirm attribute,
// check if evt.detail.target.hasAttribute('hx-confirm')
// 1. Prevent the default behavior (this will prevent the request from being issued)
evt.preventDefault();
// 2. Do your own logic here
console.log(evt.detail)
// 3. Manually issue the request when you are ready
evt.detail.issueRequest(); // or evt.detail.issueRequest(true) to skip the built-in window.confirm()
});
And here is an example using sweet alert on any element with a confirm-with-sweet-alert="{question}" attribute on it:
document.body.addEventListener('htmx:confirm', function(evt) {
// 1. The requirement to show the sweet alert is that the element has a confirm-with-sweet-alert
// attribute on it, if it doesn't we can return early and let the default behavior happen
if (!evt.detail.target.hasAttribute('confirm-with-sweet-alert')) return
// 2. Get the question from the attribute
const question = evt.detail.target.getAttribute('confirm-with-sweet-alert');
// 3. Prevent the default behavior (this will prevent the request from being issued)
evt.preventDefault();
// 4. Show the sweet alert
swal({
title: "Are you sure?",
text: question || "Are you sure you want to continue?",
icon: "warning",
buttons: true,
dangerMode: true,
}).then((confirmed) => {
if (confirmed) {
// 5. If the user confirms, we can manually issue the request
evt.detail.issueRequest(true); // true to skip the built-in window.confirm()
}
});
});
detail.elt - the element in questiondetail.etc - additional request information (mostly unused)detail.issueRequest(skipConfirmation=false) - a function that can be invoked to issue the request (should be paired with evt.preventDefault()!), if skipConfirmation is true the original window.confirm() is not executeddetail.path - the path of the requestdetail.target - the element that triggered the requestdetail.triggeringEvent - the original event that triggered this requestdetail.verb - the verb of the request (e.g. GET)detail.question - the question passed to hx-confirm attribute (only available if hx-confirm attribute is present)htmx:historyCacheErrorThis event is triggered when an attempt to save the cache to localStorage fails
detail.cause - the Exception that was thrown when attempting to save history to localStoragehtmx:historyCacheMissThis event is triggered when a cache miss occurs when restoring history
detail.xhr - the XMLHttpRequest that will retrieve the remote content for restorationdetail.path - the path and query of the page being restoredhtmx:historyCacheMissErrorThis event is triggered when a cache miss occurs and a response has been retrieved from the server
for the content to restore, but the response is an error (e.g. 404)
detail.xhr - the XMLHttpRequestdetail.path - the path and query of the page being restoredhtmx:historyCacheMissLoadThis event is triggered when a cache miss occurs and a response has been retrieved successfully from the server for the content to restore
detail.xhr - the XMLHttpRequestdetail.path - the path and query of the page being restoredhtmx:historyRestoreThis event is triggered when htmx handles a history restoration action
detail.path - the path and query of the page being restoredhtmx:beforeHistorySaveThis event is triggered before the content is saved in the history api.
detail.path - the path and query of the page being restoreddetail.historyElt - the history element being restored intohtmx:loadThis event is triggered when a new node is loaded into the DOM by htmx.
detail.elt - the newly added elementhtmx:noSSESourceErrorThis event is triggered when an element refers to an SSE event in its trigger, but no parent SSE source has been defined
detail.elt - the element with the bad SSE triggerhtmx:oobAfterSwapThis event is triggered as part of an out of band swap and behaves identically to an after swap event
detail.elt - the swapped in elementdetail.shouldSwap - if the content will be swapped (defaults to true)detail.target - the target of the swapdetail.fragment - the response fragmenthtmx:oobBeforeSwapThis event is triggered as part of an out of band swap and behaves identically to a before swap event
detail.elt - the target of the swapdetail.shouldSwap - if the content will be swapped (defaults to true)detail.target - the target of the swapdetail.fragment - the response fragmenthtmx:oobErrorNoTargetThis event is triggered when an out of band swap does not have a corresponding element in the DOM to switch with.
detail.content - the element with the bad oob idhtmx:onLoadErrorThis event is triggered when an error occurs during the load handling of an AJAX call
detail.xhr - the XMLHttpRequestdetail.elt - the element that triggered the requestdetail.target - the target of the requestdetail.exception - the exception that occurreddetail.requestConfig - the configuration of the AJAX requesthtmx:promptThis event is triggered after a prompt has been shown to the user with the hx-prompt
attribute. If this event is cancelled, the AJAX request will not occur.
detail.elt - the element that triggered the requestdetail.target - the target of the requestdetail.prompt - the user response to the prompthtmx:beforeHistoryUpdateThis event is triggered before a history update is performed. It can be
used to modify the path or type used to update the history.
detail.history - the path and type (push, replace) for the history updatedetail.xhr - the XMLHttpRequestdetail.target - the target of the requestdetail.requestConfig - the configuration of the AJAX requesthtmx:pushedIntoHistoryThis event is triggered after a URL has been pushed into history.
detail.path - the path and query of the URL that has been pushed into historyhtmx:replacedInHistoryThis event is triggered after a URL has been replaced in history.
detail.path - the path and query of the URL that has been replaced in historyhtmx:responseErrorThis event is triggered when an HTTP error response occurs
detail.xhr - the XMLHttpRequestdetail.elt - the element that triggered the requestdetail.target - the target of the requestdetail.requestConfig - the configuration of the AJAX requesthtmx:sendAbortThis event is triggered when a request is aborted
detail.xhr - the XMLHttpRequestdetail.elt - the element that triggered the requestdetail.target - the target of the requestdetail.requestConfig - the configuration of the AJAX requesthtmx:sendErrorThis event is triggered when a network error prevents an HTTP request from occurring
detail.xhr - the XMLHttpRequestdetail.elt - the element that triggered the requestdetail.target - the target of the requestdetail.requestConfig - the configuration of the AJAX requesthtmx:sseErrorThis event is triggered when an error occurs with an SSE source
detail.elt - the element with the bad SSE sourcedetail.error - the errordetail.source - the SSE sourcehtmx:swapErrorThis event is triggered when an error occurs during the swap phase
detail.xhr - the XMLHttpRequestdetail.elt - the element that triggered the requestdetail.target - the target of the requestdetail.requestConfig - the configuration of the AJAX requesthtmx:targetErrorThis event is triggered when a bad selector is used for a hx-target attribute (e.g. an
element ID without a preceding #)
detail.elt - the element that triggered the requestdetail.target - the bad CSS selectorhtmx:timeoutThis event is triggered when a request timeout occurs. This wraps the typical timeout event of XMLHttpRequest.
Timeout time can be set using htmx.config.timeout or per element using hx-request
detail.elt - the element that dispatched the requestdetail.xhr - the XMLHttpRequestdetail.target - the target of the requestdetail.requestConfig - the configuration of the AJAX requesthtmx:triggerThis event is triggered whenever an AJAX request would be, even if no AJAX request is specified. It
is primarily intended to allow hx-trigger to execute client-side scripts; AJAX requests have more
granular events available, like htmx:beforeRequest or htmx:afterRequest.
detail.elt - the element that triggered the requesthtmx:validateUrlThis event is triggered before a request is made, allowing you to validate the URL that htmx is going to request. If
preventDefault() is invoked on the event, the request will not be made.
document.body.addEventListener('htmx:validateUrl', function (evt) {
// only allow requests to the current server as well as myserver.com
if (!evt.detail.sameHost && evt.detail.url.hostname !== "myserver.com") {
evt.preventDefault();
}
});
detail.elt - the element that triggered the requestdetail.url - the URL Object representing the URL that a request will be sent to.detail.sameHost - will be true if the request is to the same host as the documenthtmx:validation:validateThis event is triggered before an element is validated. It can be used with the elt.setCustomValidity() method
to implement custom validation rules.
<form hx-post="/test">
<input _="on htmx:validation:validate
if my.value != 'foo'
call me.setCustomValidity('Please enter the value foo')
else
call me.setCustomValidity('')"
name="example">
</form>
detail.elt - the element to be validatedhtmx:validation:failedThis event is triggered when an element fails validation.
detail.elt - the element that failed validationdetail.message - the validation error messagedetail.validity - the validity object, which contains properties specifying how validation failedhtmx:validation:haltedThis event is triggered when a request is halted due to validation errors.
detail.elt - the element that triggered the requestdetail.errors - an array of error objects with the invalid elements and errors associated with themhtmx:xhr:abortThis event is triggered when an ajax request aborts
detail.elt - the element that triggered the requesthtmx:xhr:loadstartThis event is triggered when an ajax request starts
detail.elt - the element that triggered the requesthtmx:xhr:loadendThis event is triggered when an ajax request finishes
detail.elt - the element that triggered the requesthtmx:xhr:progressThis event is triggered periodically when an ajax request that supports progress is in flight
detail.elt - the element that triggered the request