Cannot read property 'innerHTML' of undefined

问题

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 !

回答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.

来源：https://stackoverflow.com/questions/38785861/cannot-read-property-innerhtml-of-undefined