A data source can store numbers as strings. Telephone numbers, zip codes, user IDs, and invoice numbers are some of the numbers that might be stored as strings. To manipulate these numbers mathematically, you need to convert them to a numeric type using the parseInt( ) or parseFloat( ) JavaScript function.

The following example converts an invoice ID to an integer and adds 10 to it:

If invoiceID is 1225, this expression returns 1235. If parseInt( ) is not used to convert invoiceID to a real number, the result of adding 10 to invoiceID is 122510.