XMLHttpRequestEventTarget.onloadstart - Web APIs
the xmlhttprequesteventtarget.onloadstart is the function called when an xmlhttprequest transaction starts transferring data.
... syntax xmlhttprequest.onloadstart = callback; values callback is the function to be called when the transaction begins to transfer data.
... example var xmlhttp = new xmlhttprequest(), method = 'get', url = 'https://developer.mozilla.org/'; xmlhttp.open(method, url, true); xmlhttp.onloadstart = function () { console.log("download underway"); }; xmlhttp.send(); specifications specification status comment xmlhttprequest living standard whatwg living standard ...

GlobalEventHandlers.onloadstart - Web APIs
the onloadstart property sets and returns the event handler for the loadstart event.
... syntax element.onloadstart = handlerfunction; var handlerfunction = element.onloadstart; handlerfunction should be either null or a javascript function specifying the handler for the event.

GlobalEventHandlers.onloadstart - Web APIs
the onloadstart property of the globaleventhandlers mixin is an eventhandler representing the code to be called when the loadstart event is raised (when progress has begun on the loading of a resource.) syntax img.onloadstart = funcref; value funcref is the handler function to be called when the resource's loadstart event fires.
...'load', then 'loadend' image.addeventlistener('load', function(e) { console.log('image loaded'); }); image.addeventlistener('loadstart', function(e) { console.log('image load started'); }); image.addeventlistener('loadend', function(e) { console.log('image load finished'); }); specifications specification status comment html living standardthe definition of 'onloadstart' in that specification.

Index - Web APIs
1514 globaleventhandlers.onloadend api, dom, event handler, globaleventhandlers, property, reference, web, events, onloadend the onloadend property of the globaleventhandlers mixin is an eventhandler representing the code to be called when the loadend event is raised (when progress has stopped on the loading of a resource.) 1515 globaleventhandlers.onloadstart the onloadstart property sets and returns the event handler for the loadstart event.
... 1516 globaleventhandlers.onloadstart api, dom, event handler, globaleventhandlers, property, reference, web, events, onloadstart the onloadstart property of the globaleventhandlers mixin is an eventhandler representing the code to be called when the loadstart event is raised (when progress has begun on the loading of a resource.) 1517 globaleventhandlers.onlostpointercapture api, event handler, globaleventhandlers, html dom, property, reference, events, onlostpointercapture the onlostpointercapture property of the globaleventhandlers mixin is an eventhandler that processes lostpointercapture events.
... 5214 xmlhttprequesteventtarget.onloadstart api, event handler, property, reference, web, xmlhttprequesteventtarget the xmlhttprequesteventtarget.onloadstart is the function called when an xmlhttprequest transaction starts transferring data.

FileReader - Web APIs
filereader.onloadstart a handler for the loadstart event.
... also available via the onloadstart property.

nsIXMLHttpRequestEventTarget
onloadstart nsidomeventlistener a javascript function object that gets invoked exactly once when the operation begins.

nsIXMLHttpRequestUpload
6 introduced gecko 1.9.1 inherits from: nsidomeventtarget last changed in gecko 1.9.1 (firefox 3.5 / thunderbird 3.0 / seamonkey 2.0) attributes attribute type description onabort nsidomeventlistener onerror nsidomeventlistener onload nsidomeventlistener onloadstart nsidomeventlistener onprogress nsidomeventlistener see also nsixmlhttprequest nsixmlhttprequesteventtarget xmlhttprequest using xmlhttprequest ...

Document - Web APIs
globaleventhandlers.onloadend is an eventhandler representing the code to be called when the loadend event is raised (when progress has stopped on the loading of a resource.) globaleventhandlers.onloadstart is an eventhandler representing the code to be called when the loadstart event is raised (when progress has begun on the loading of a resource.) globaleventhandlers.onlostpointercapture is an eventhandler representing the code to be called when the lostpointercapture event type is raised.

FileReader: loadstart event - Web APIs
bubbles no cancelable no interface progressevent event handler property filereader.onloadstart examples live example html <div class="example"> <div class="file-select"> <label for="avatar">choose a profile picture:</label> <input type="file" id="avatar" name="avatar" accept="image/png, image/jpeg"> </div> <img src="" class="preview" height="200" alt="image preview..."> <div class="event-log"> <label>event log:</label> <textarea readonly class="event-log-contents"></textarea> </div> </div> css img.preview { margin: 1rem 0; } .event-log-contents { width: 18rem; height: 5rem; bor...

GlobalEventHandlers - Web APIs
globaleventhandlers.onloadend is an eventhandler representing the code to be called when the loadend event is raised (when progress has stopped on the loading of a resource.) globaleventhandlers.onloadstart is an eventhandler representing the code to be called when the loadstart event is raised (when progress has begun on the loading of a resource.) globaleventhandlers.onlostpointercapture is an eventhandler representing the code to be called when the lostpointercapture event type is raised.

HTMLMediaElement: loadstart event - Web APIs
bubbles no cancelable no interface event event handler property onloadstart examples live example html <div class="example"> <button type="button">load video</button> <video controls width="250"></video> <div class="event-log"> <label>event log:</label> <textarea readonly class="event-log-contents"></textarea> </div> </div> css .event-log-contents { width: 18rem; height: 5rem; border: 1px solid black; margin: .2rem; padding: .2rem; } .example { display: grid; grid-template-areas: "button log" "video log"; } button { grid-area: button; width: 10rem; margin: .5rem 0; } video { ...

XMLHttpRequest: loadstart event - Web APIs
bubbles no cancelable no interface progressevent event handler property onloadstart examples live example html <div class="controls"> <input class="xhr success" type="button" name="xhr" value="click to start xhr (success)" /> <input class="xhr error" type="button" name="xhr" value="click to start xhr (error)" /> <input class="xhr abort" type="button" name="xhr" value="click to start xhr (abort)" /> </div> <textarea readonly class="event-log"></textarea> css .event-log { width: 25rem; height: 4rem; border: 1px solid black; margin: .5rem; padding: .2rem; } input { width: 11rem; margin: .5rem; } js const xhrbuttonsuccess = docu...

XMLHttpRequest.upload - Web APIs
the following events can be triggered on an upload object and used to monitor the upload: event event listener description loadstart onloadstart the upload has begun.

XMLHttpRequest - Web APIs
also available via the onloadstart property.

XMLHttpRequestEventTarget - Web APIs
xmlhttprequesteventtarget.onloadstart contains the function that gets called when the http request first begins loading data and the loadstart event is received by this object.