A bunch of random crap working towards the first (simplest) upload mechanism

static/script.js

@@ -0,0 +1,45 @@
+function uploadFiles(submitButtonID, fileInputID, progressBarID, targetEndpoint, otherData) {
+    const submitButton = document.getElementById(submitButtonID)
+    submitButton.disabled = true
+
+    const files = document.getElementById(fileInputID).files
+
+    if (!files[0]) {
+        alert('Please select at least one file')
+        submitButton.disabled = false
+        return
+    }
+
+    const formData = new FormData()
+    
+    for(var i = 0; i < files.length; i++) {
+        formData.append("files[]", files[i])
+    }
+
+    for(const key in otherData) {
+        formData.append(key, otherData[key])
+    }
+
+    var xhr = new XMLHttpRequest()
+    xhr.open("POST", targetEndpoint)
+    xhr.onload = function() {
+        if (xhr.status === 200) {
+            window.location.href = "/"
+        } else {
+            alert("Something went wrong during the upload, please try again later")
+            submitButton.disabled = false
+        }
+    }
+    xhr.upload.onprogress = function(event) {
+        if(event.lengthComputable) {
+            const percentComplete = (event.loaded / event.total) * 100
+            document.getElementById(progressBarID).value = percentComplete
+        }
+    }
+    xhr.onerror = function() {
+        alert("An error occurred, please try again later")
+        submitButton.disabled = false
+    }
+
+    xhr.send(formData)
+}