Cannot read property 'innerHTML' of undefined

Question

I'm trying to test an app in salesforce lightning component, but when I load the app (I try this app) I got the error

Cannot read property 'innerHTML' of undefined

The associated code is here :

 !(function(t, e) {
     var r = function(e) {
             (t.execScript || function(e) {
                 t["eval"].call(t, e)
             })(e)
         },
         i = function(t, e) {
             return t instanceof(e || Array)
         },
         s = document,
         n = "getElementsByTagName",
         a = "length",
         c = "readyState",
         l = "onreadystatechange",
         u = s[n]("script"),
         o = u[u[a] - 1],
         f = o.innerHTML.replace(/^\s+|\s+$/g, "");
     if (!t.ljs) {
         var h = o.src.match(/checkLoaded/) ? 1 : 0,
             d = s[n]("head")[0] || s.documentElement,
             p = function(t) {
                 var e = {};
                 e.u = t.replace(/#(=)?([^#]*)?/g, function(t, r, i) {
                     e[r ? "f" : "i"] = i;
                     return ""
                 });
                 return e
             },
             v = function(t, e, r) {
                 var i = s.createElement(t),
                     n;
                 if (r) {
                     if (i[c]) {
                         i[l] = function() {
                             if (i[c] === "loaded" || i[c] === "complete") {
                                 i[l] = null;
                                 r()
                             }
                         }
                     } else {
                         i.onload = r
                     }
                 }
                 for (n in e) {
                     e[n] && (i[n] = e[n])
                 }
                 d.appendChild(i)
             },
             m = function(t, e) {
                 if (this.aliases && this.aliases[t]) {
                     var r = this.aliases[t].slice(0);
                     i(r) || (r = [r]);
                     e && r.push(e);
                     return this.load.apply(this, r)
                 }
                 if (i(t)) {
                     for (var s = t[a]; s--;) {
                         this.load(t[s])
                     }
                     e && t.push(e);
                     return this.load.apply(this, t)
                 }
                 if (t.match(/\.js\b/) || t.match(/\.sfjs\b/)) {
                     t = t.replace(".sfjs", "");
                     return this.loadjs(t, e)
                 } else if (t.match(/\.css\b/) || t.match(/\.sfcss\b/)) {
                     t = t.replace(".sfcss", "");
                     return this.loadcss(t, e)
                 } else {
                     return this.loadjs(t, e)
                 }
             },
             y = {},
             g = {
                 aliases: {},
                 loadjs: function(t, r) {
                     var i = p(t);
                     t = i.u;
                     if (y[t] === true) {
                         r && r();
                         return this
                     } else if (y[t] !== e) {
                         if (r) {
                             y[t] = function(t, e) {
                                 return function() {
                                     t && t();
                                     e && e()
                                 }
                             }(y[t], r)
                         }
                         return this
                     }
                     y[t] = function(e) {
                         return function() {
                             y[t] = true;
                             e && e()
                         }
                     }(r);
                     r = function() {
                         y[t]()
                     };
                     v("script", {
                         type: "text/javascript",
                         src: t,
                         id: i.i,
                         onerror: function(t) {
                             if (i.f) {
                                 var e = t.currentTarget;
                                 e.parentNode.removeChild(e);
                                 v("script", {
                                     type: "text/javascript",
                                     src: i.f,
                                     id: i.i
                                 }, r)
                             }
                         }
                     }, r);
                     return this
                 },
                 loadcss: function(t, e) {
                     var r = p(t);
                     t = r.u;
                     y[t] || v("link", {
                         type: "text/css",
                         rel: "stylesheet",
                         href: t,
                         id: r.i
                     });
                     y[t] = true;
                     e && e();
                     return this
                 },
                 load: function() {
                     var t = arguments,
                         r = t[a];
                     if (r === 1 && i(t[0], Function)) {
                         t[0]();
                         return this
                     }
                     m.call(this, t[0], r <= 1 ? e : function() {
                         g.load.apply(g, [].slice.call(t, 1))
                     });
                     return this
                 },
                 addAliases: function(t) {
                     for (var e in t) {
                         this.aliases[e] = i(t[e]) ? t[e].slice(0) : t[e]
                     }
                     return this
                 }
             };
         if (h) {
             var j, b, x, A;
             for (j = 0, b = u[a]; j < b; j++) {
                 (A = u[j].getAttribute("src")) && (y[A.replace(/#.*$/, "")] = true)
             }
             x = s[n]("link");
             for (j = 0, b = x[a]; j < b; j++) {
                 (x[j].rel === "stylesheet" || x[j].type === "text/css") && (y[x[j].getAttribute("href").replace(/#.*$/, "")] = true)
             }
         }
         t.ljs = g
     }
     f && r(f)
 })(window);

But I'm a novice with javascript and I don't know how to fix it (i'd like to test this app)

Thanks !

Answer 1

That just means that the element that you are looking for does not exist:

var elementNotFound = document.getElementById("noSuchId"); // Does not exist
console.log("The element:", elementNotFound);
console.log(elementNotFound.innerHTML);

As you have posted the mimified JavaScript and no HTML, I don't know how to help further then saying: Make use the ID you are using to find the element is correct and has no spelling mistakes, and that the element is actually in the HTML.

Hope this helps.