How can I get Instant notification if a download fails, instead of sifting through the whole library later looking for a fail message

Question

sometimes I download hundreds of articles, pdf's, videos etc at one sitting, and cannot stop to watch whether or not some few of the items "fail" to completely download. Later, when scrolling down the whole list of recent downloads in the library I try to squint and see the tiny words notifying of a failed download but it is easy to miss the warning plus when there are hundreds of items it is VERY time-consuming to double click each item to attempt a re-download . . it usually DOES re-download ok BUT selecting this process sends the cursor back to the top of the library listings and now it takes forever to find your place back in the area where there were several "fails" listed together to continue the correction process for the whole list. Would be SO VERY MUCH better if and when a particular download fails, that a pop up window message would alert to that fact and a simple click within said window would automatically re-start the download, etc. That way a vital article would not later be discovered to have no content or error message, etc, just when one needed it and perhaps was not able to go online to fix it.

Answer 1

You can run this code in the Browser Console (Firefox/Tools > Web Developer) to add a tooltip to the icon of each item in that list.
You probably need to scroll the full list to make Firefox update all attributes and you need to rerun the code in the browser console via cursor Up and Enter to update all tooltips after having done a new download.
If you run the code then you get a pop-up that shows some information of all selected items (Ctrl click multiple items).
You can open the Browser Console (Firefox/Tools > Web Developer).
Paste the JavaScript code in the command line and press the Enter key to run the code.
*Toggle the devtools.chrome.enabled pref on the <b>about:config</b> page to true to enable the command line
<pre><nowiki>var {classes:Cc,interfaces:Ci} = Components;
var wm = Cc["@mozilla.org/appshell/window-mediator;1"].getService(Ci.nsIWindowMediator);
var win = wm.getMostRecentWindow("Places:Organizer");
if(d=win.document.getElementById("downloadsRichListBox")){
var C=[],L=[],r,R;
r=d.getElementsByTagName("richlistitem");
for(i=0;R=r[i];i++){
var tt=R.getAttribute("image").replace(/^moz-icon:[/][/]([^?]+)[?]size=\d+$/,"$1");
var tT=[];
var nD=R.getAttribute("displayName");
tT.push("["+(i+1)+"] ["+nD+"]");
tT.push("FILE: "+tt);
var eT=R.getAttribute("state")||0;
var sT=R.getAttribute("status");
tT.push("STATUS["+eT+"]: "+sT);
R.setAttribute("tooltiptext",tT.join("\n"));
if(R.getAttribute("selected")=="true"){C.push(tT);L.push(tt)}
if(C){if(prompt(C.join("\n"),C)){prompt(L.join("\n"),L);}}
</nowiki></pre>