Baseline Widely available
Note: This feature is available in Web Workers.
The abort
event of the FileReader
interface is fired when a read has been aborted: for instance because the program called FileReader.abort()
.
This event is not cancelable and does not bubble.
SyntaxUse the event name in methods like addEventListener()
, or set an event handler property.
addEventListener("abort", (event) => { })
onabort = (event) => { }
Event type Event properties
Also inherits properties from its parent Event
.
ProgressEvent.lengthComputable
Read only
A boolean flag indicating if the total work to be done, and the amount of work already done, by the underlying process is calculable. In other words, it tells if the progress is measurable or not.
ProgressEvent.loaded
Read only
A 64-bit unsigned integer value indicating the amount of work already performed by the underlying process. The ratio of work done can be calculated by dividing total
by the value of this property. When downloading a resource using HTTP, this only counts the body of the HTTP message, and doesn't include headers and other overhead.
ProgressEvent.total
Read only
A 64-bit unsigned integer representing the total amount of work that the underlying process is in the progress of performing. When downloading a resource using HTTP, this is the Content-Length
(the size of the body of the message), and doesn't include the headers and other overhead.
<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 for="eventLog">Event log:</label>
<textarea readonly class="event-log-contents" id="eventLog"></textarea>
</div>
</div>
img.preview {
margin: 1rem 0;
}
.event-log-contents {
width: 18rem;
height: 5rem;
border: 1px solid black;
margin: 0.2rem;
padding: 0.2rem;
resize: none;
}
.example {
display: grid;
grid-template-areas:
"select log"
"preview log";
}
.file-select {
grid-area: select;
}
.preview {
grid-area: preview;
}
.event-log {
grid-area: log;
}
.event-log > label {
display: block;
}
JavaScript
const fileInput = document.querySelector('input[type="file"]');
const preview = document.querySelector("img.preview");
const eventLog = document.querySelector(".event-log-contents");
const reader = new FileReader();
function handleEvent(event) {
eventLog.textContent += `${event.type}: ${event.loaded} bytes transferred\n`;
if (event.type === "load") {
preview.src = reader.result;
}
}
function addListeners(reader) {
reader.addEventListener("loadstart", handleEvent);
reader.addEventListener("load", handleEvent);
reader.addEventListener("loadend", handleEvent);
reader.addEventListener("progress", handleEvent);
reader.addEventListener("error", handleEvent);
reader.addEventListener("abort", handleEvent);
}
function handleSelected(e) {
eventLog.textContent = "";
const selectedFile = fileInput.files[0];
if (selectedFile) {
addListeners(reader);
reader.readAsDataURL(selectedFile);
}
reader.abort();
}
fileInput.addEventListener("change", handleSelected);
Result Specifications Browser compatibility See also
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4