Deal with failed parameter queries properly

dev/admin.htm

@@ -10,6 +10,17 @@ async function queryParams() {
   const json = await req.json()
   //console.log(json)
   //console.log(Object.keys(json))
+  if (!req.ok) {
+    var err_msg = null
+    if (req.body != null) {
+      err_msg = await req.text()
+    }
+    if (err_msg != null) {
+      status("query failed: " + resp.status + " " + err_msg)
+    } else {
+      status("query failed: " + resp.status)
+    }
+  }
   status('parameter query successful!')
   const paramList = document.getElementById('param-list')
   while (paramList.firstChild) {