Question

I noticed that stackoverflow has some JS code which generates: a warning with “Stack Overflow requires external JavaScript from another domain, which is blocked or failed to load.”. This happened to me a moment ago when Google Analytics didn’t load correctly.

How would I do something like this?

Note: I could have a but all other JS loads correctly this is only for google analytics which sometimes either never loads or takes forever.

When I check the code they have:

StackExchange.init = function () {
    var e = function (a) {
        if (!window.jQuery) if ("complete" != document.readyState) setTimeout(function () {
            e(a)
        }, 1E3);
        else {
            var d = document.createElement("div");
            d.id = "noscript-padding";
            var g = document.createElement("div");
            g.id = "noscript-warning";
            g.innerHTML = a + " requires external JavaScript from another domain, which is blocked or failed to load.";
            document.body.insertBefore(d, document.body.firstChild);
            document.body.appendChild(g)
        }

But I am not sure what is going on with the setTimeout()

Answer 1

With setTimeout they wait until the page is loaded completely. The function e calls itself until document.readyState is complete where 1E3 is 1000 => 1 second:

if ("complete" != document.readyState) setTimeout(function () { e(a) }, 1E3);

If you like to do the same for Google Analytics check out: javascript – Detect if Google Analytics is loaded yet?