XMLHttpRequestUpload
注意：此功能在 Web Workers 中可用，但 Service Workers 除外。
XMLHttpRequestUpload 介面代表了特定 XMLHttpRequest 的上傳過程。它是一個不透明物件，代表了底層、依賴於瀏覽器的上傳過程。它是一個 XMLHttpRequestEventTarget，可以透過呼叫 XMLHttpRequest.upload 獲取。
例項屬性
此介面沒有特定的屬性，但繼承了 XMLHttpRequestEventTarget 和 EventTarget 的屬性。
例項方法
此介面沒有特定的方法，但繼承了 XMLHttpRequestEventTarget 和 EventTarget 的方法。
事件
此介面沒有特定的事件，但繼承了 XMLHttpRequestEventTarget 的事件。
示例
使用超時上傳檔案
這允許您將檔案上傳到伺服器；它在上傳過程中顯示一個進度條，以及一條包含進度和結果（成功或失敗）的訊息。一箇中止按鈕允許停止上傳。
HTML
html
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width" />
<title>XMLHttpRequestUpload test</title>
<link rel="stylesheet" href="xhrupload_test.css" />
<script src="xhrupload_test.js"></script>
</head>
<body>
<main>
<h1>Upload a file</h1>
<p>
<label for="file">File to upload</label><input type="file" id="file" />
</p>
<p>
<progress></progress>
</p>
<p>
<output></output>
</p>
<p>
<button disabled id="abort">Abort</button>
</p>
</main>
</body>
</html>
CSS
css
body {
background-color: lightblue;
}
main {
margin: 50px auto;
text-align: center;
}
#file {
display: none;
}
label[for="file"] {
background-color: lightgrey;
padding: 10px;
}
progress {
display: none;
}
progress.visible {
display: inline;
}
JavaScript
js
const fileInput = document.getElementById("file");
const progressBar = document.querySelector("progress");
const log = document.querySelector("output");
const abortButton = document.getElementById("abort");
fileInput.addEventListener("change", () => {
const xhr = new XMLHttpRequest();
xhr.timeout = 2000; // 2 seconds
// Link abort button
abortButton.addEventListener(
"click",
() => {
xhr.abort();
},
{ once: true },
);
// When the upload starts, we display the progress bar
xhr.upload.addEventListener("loadstart", (event) => {
progressBar.classList.add("visible");
progressBar.value = 0;
progressBar.max = event.total;
log.textContent = "Uploading (0%)…";
abortButton.disabled = false;
});
// Each time a progress event is received, we update the bar
xhr.upload.addEventListener("progress", (event) => {
progressBar.value = event.loaded;
log.textContent = `Uploading (${(
(event.loaded / event.total) *
100
).toFixed(2)}%)…`;
});
// When the upload is finished, we hide the progress bar.
xhr.upload.addEventListener("loadend", (event) => {
progressBar.classList.remove("visible");
if (event.loaded !== 0) {
log.textContent = "Upload finished.";
}
abortButton.disabled = true;
});
// In case of an error, an abort, or a timeout, we hide the progress bar
// Note that these events can be listened to on the xhr object too
function errorAction(event) {
progressBar.classList.remove("visible");
log.textContent = `Upload failed: ${event.type}`;
}
xhr.upload.addEventListener("error", errorAction);
xhr.upload.addEventListener("abort", errorAction);
xhr.upload.addEventListener("timeout", errorAction);
// Build the payload
const fileData = new FormData();
fileData.append("file", fileInput.files[0]);
// Theoretically, event listeners could be set after the open() call
// but browsers are buggy here
xhr.open("POST", "upload_test.php", true);
// Note that the event listener must be set before sending (as it is a preflighted request)
xhr.send(fileData);
});
規範
| 規範 |
|---|
| XMLHttpRequest # xmlhttprequestupload |
瀏覽器相容性
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