JavaScript Program to Check Whether a String Contains a Substring

To understand this example, you should have the knowledge of the following JavaScript programming topics:

Example 1: Check String with includes()

Output

Enter a string: JavaScript is fun
Enter a string that you want to check: fun
The string contains fun

The includes() method is used with the if...else statement to check whether a string contains the characters of a specified string.

Note: The includes() method is case-sensitive. Hence, fun and Fun are different.

Output

Enter a string: JavaScript is fun
Enter a string that you want to check: fun
The string contains fun

In the above program, the indexOf() method is used with the if...else statement to check if a string contains a substring.

The indexOf() method searches a string and returns the position of the first occurrence. When a substring cannot be found, it returns -1.

Note: The indexOf() method is case sensitive.

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