diff --git a/fetchEvents.js b/fetchEvents.js
index 47e514a..c0bf5d0 100644
--- a/fetchEvents.js
+++ b/fetchEvents.js
@@ -22,7 +22,7 @@ window.fetch = function(url, init) {
                         response: response
                     }
                 }));
-        } if(response.status >= 400 && response.status < 600) {
+        } else if(response.status >= 400 && response.status < 600) {
             window.dispatchEvent(
                 new CustomEvent("fetchResponseError", {
                     detail: {
diff --git a/index.html b/index.html
index 22888e4..12a40af 100644
--- a/index.html
+++ b/index.html
@@ -112,12 +112,16 @@ <h4>
                         }
                     });
                     window.addEventListener("fetchResponseSuccess", event => {
-                        event.detail.response.json().then(content => {
-                            document.getElementById(window.logId).innerHTML+="<br/>Fetch response success. Url: ["+event.detail.url+"]. HTTP Method: ["+event.detail.init.method+"]. Response: "+content+".";
-                        });
+                        if(window.logId) {
+                            event.detail.response.json().then(jsonResponse => {
+                                document.getElementById(window.logId).innerHTML+="<br/>Fetch response success. Url: ["+event.detail.url+"]. HTTP Method: ["+event.detail.init.method+"]. Response: "+jsonResponse+".";
+                            });
+                        }
                     });
                     window.addEventListener("fetchResponseError", event => {
-                        document.getElementById(window.logId).innerHTML+="<br/>Fetch response error. Url: ["+event.detail.url+"]. HTTP Method: ["+event.detail.init.method+"]. Status: ["+event.detail.response.status+"]";
+                        if(window.logId) {
+                            document.getElementById(window.logId).innerHTML+="<br/>Fetch response error. Url: ["+event.detail.url+"]. HTTP Method: ["+event.detail.init.method+"]. Status: ["+event.detail.response.status+"]";
+                        }
                     });
                     window.addEventListener("fetchError", event => {
                         if(window.logId) {