Javascript popup to debug : add a small popup to the window with a value. I use it in a bookmark after minifying it.

debug-popup.js

(function() {
var text = "Somme des salaires : ";

// popup
var x = document.createElement("div");
x.appendChild(document.createTextNode(text));
x.setAttribute("style", "border: 3px solid black; background: white; height: 30px; width: 200px; padding: 15px; position: fixed; top: 20%; right: 2%;");

var close = document.createElement("a");
close.appendChild(document.createTextNode("X"));
close.addEventListener("click", function() { document.body.removeChild(x); });
close.style.position = "absolute";
close.style.right = "5px";
close.style.top = "5px";
x.appendChild(close);

document.body.appendChild(x);

x.addEventListener ("mousedown", eleMouseDown);

function eleMouseDown (ev) {
	document.addEventListener ("mousemove", eleMouseMove);
}

function eleMouseMove (ev) {
	x.style.position = "absolute";
	x.style.left = ev.pageX + "px";
	x.style.top = ev.pageY + "px";
	document.addEventListener ("mouseup" , eleMouseUp , false);
}

function eleMouseUp () {
	document.removeEventListener ("mousemove" , eleMouseMove , false);
	document.removeEventListener ("mouseup" , eleMouseUp , false);
}

})();