From 49b0543cfc5d8efe1a7d97181c500aef8aa488dd Mon Sep 17 00:00:00 2001
From: Mischa POSLAWSKY <perl@shiar.org>
Date: Sun, 27 Dec 2020 03:46:55 +0100
Subject: [PATCH] progress: disable submit button while posting

Prevent duplicates from unavoidable double clicks.
---
 progress.js | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/progress.js b/progress.js
index 575b98e..601fec0 100644
--- a/progress.js
+++ b/progress.js
@@ -2,11 +2,13 @@ function showsize(bytes) {
 	return (bytes / 1024 / 1024).toFixed(2);
 }
 
-function trackupload(input) {
-	if (!input.value) {
-		return true; // default form action
-	}
+function enablesubmit(form) {
+	let submit = form.querySelector('input[type="submit"]:disabled');
+	if (!submit) return;
+	submit.disabled = false;
+}
 
+function trackupload(input) {
 	var progress = document.getElementById('progress');
 	if (!progress) {
 		progress = document.createElement('DIV');
@@ -35,17 +37,20 @@ function trackupload(input) {
 		else {
 			progress.textContent = 'fout';
 			progress.innerHTML += ': <small>' + e.target.responseText + '</small>';
+			enablesubmit(input.form);
 		}
 		progress.style.width = '100%';
 		input.parentNode.removeChild(cancel);
 	}, false);
 	ajax.addEventListener('error', function (e) {
 		progress.textContent = 'mislukt: ' + e.target.responseText;
+		enablesubmit(input.form);
 	}, false);
 	ajax.addEventListener('abort', function (e) {
 		progress.textContent = 'afgebroken';
 		input.parentNode.removeChild(cancel);
 		input.parentNode.removeChild(progress.parentNode);
+		enablesubmit(input.form);
 	}, false);
 
 	ajax.open('POST', input.form.action);
@@ -57,15 +62,20 @@ function trackupload(input) {
 	cancel.onclick = function () { ajax.abort() };
 	cancel.style.float = 'left';
 	input.parentNode.insertBefore(cancel, progress.parentNode);
-	return false;
 }
 
 document.addEventListener('DOMContentLoaded', e => {
-	for (let row of document.forms[0].elements) {
-		if (row.type == 'file') {
-			row.form.onsubmit = () => {
-				return trackupload(row);
-			};
-		}
+	for (let form of document.forms) {
+		form.addEventListener('submit', e => {
+			if (e.explicitOriginalTarget) {
+				e.explicitOriginalTarget.disabled = true;
+			}
+			if (upload = e.target.querySelector('input[type="file"]')) {
+				if (upload.value) {
+					e.preventDefault();
+					trackupload(upload);
+				}
+			}
+		});
 	}
 });
-- 
2.30.0