When a string and a number are added then instead of addition, concatenation takes place. They both ended up attaching each other. But if we need to add them we need to convert the string into an integer. In this situation, '+' operator comes into the picture. It actually, converts the string into integer and helps to add them.
Example-1
In the following example, the string is directly added to the number without any conversion. Therefore concatenation takes place instead of addition as shown in the output.
<html> <body> <script> const string = "100"; const number = 5; document.write(string + number); </script> </body> </html>
Output
1005
Example-2
In the following example, '+' operator is used to convert the string into the number. So, instead of concatenation, the addition took place and the result is displayed in the output.
<html> <body> <script> const string = "100"; const number = 5; document.write(+string + number); </script> </body> </html>
Output
105
Example-3
In the following example, parseInt is used to convert the string into the number. It does the same operation as '+' operator.
<html> <body> <script> const string = "100"; const number = 5; document.write(parseInt(string) + number); </script> </body> </html>
Output
105