Formatting examples, added example based on note (#21186)

would like some feedback on my extra example :)

guide/english/javascript/if-else-statement/index.md

@@ -73,16 +73,23 @@ const num = someCondition ? 1 : 2;
 ```
 
 **Using** `else if`:
-
 ```javascript
-if (x < 10){
+    // Categorising any number x as a small, medium, or large number  
-    return "Small number";
+    if (x < 10)
-}else if (x < 50){
+        return "Small number";
-    return "Medium number";
+    else if (x < 50)
-}else if (x < 100){
+        return "Medium number";
-    return "Large number";
+    else if (x < 100)
-}else {
+        return "Large number";
-    flag = 1;
+    else {
-    return "Invalid number";
+        flag = 1;
-}
+        return "Invalid number";
+    }
 ```
+
+**Using** `if` **alone**:
+```javascript
+    // This function can also act as a Boolean
+    if (x < 30) {
+        return "true";
+    }