Fixed code formatting (#23068)

Added curly brackets where they had been left out of the code snippets. Also fixed two grammatical errors on line 52

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

@@ -8,24 +8,26 @@ The `if` statement executes a statement if a specified condition is `true`. If t
 **Note:** The `else` statement is optional.
 
 ```javascript
-if (condition)
+if (condition) {
     /* do something */
-else
+} else {
     /* do something else */
+}
 ```
 
 
 Multiple `if...else` statements can be chained to create an `else if` clause. This specifies a new condition to test and can be repeated to test multiple conditions, checking until a true statement is presented to execute.
 
 ```javascript
-if (condition1)
+if (condition1) {
     /* do something */
-else if (condition2)
+} else if (condition2) {
     /* do something else */
-else if (condition3)
+} else if (condition3) {
     /* do something else */
-else
+} else {
     /* final statement */
+}
 ```
 
 **Note:** If you want to execute more than one statement in the `if`, `else` or `else if` part, curly braces are required around the statements:
@@ -63,10 +65,11 @@ const num = someCondition ? 1 : 2;
 
 **Using** `if...else`:
 ```javascript
-    // If x=5 then z=7 and q=42 else z=19.
-    if (x === 5) {
+// If x = 5, then z = 7 and q = 42.
+// If x is not 5, then z = 19.
+if (x == 5) {
   z = 7;
-      q = 42;
+  q = 42
 } else {
   z = 19;
 }
@@ -74,14 +77,13 @@ const num = someCondition ? 1 : 2;
 
 **Using** `else if`:
 ```javascript
-    // Categorising any number x as a small, medium, or large number  
-    if (x < 10)
+if (x < 10) {
   return "Small number";
-    else if (x < 50)
+} else if (x < 50) {
   return "Medium number";
-    else if (x < 100)
+} else if (x < 100) {
   return "Large number";
-    else {
+} else {
   flag = 1;
   return "Invalid number";
 }