When I was a kid, telephones had rotary dials, not push buttons, and exchanges had names; my grandmother was in the Underhill 8 exchange.If you were calling someone in the same exchange as you were, you only had to dial the last four digits of the number.If you choose to participate, the online survey will be presented to you when you leave the Msdn Web site. You can check if a business is registered to trade cross-border within the EU with the EU's VIES on the web tool.Telephone numbers can be written as ten digits, or with dashes, spaces, or dots between the three segments, or with the area code parenthesized; both the area code and any white space between segments are optional.Thus, all of the following are valid telephone numbers: 1234567890, 123-456-7890, 123.456.7890, (123)456-7890, (123) 456-7890 (note the white space following the area code), and 456-7890.
Modern American telephone numbers have ten digits, segmented as a three-digit area code, a three-digit exchange code, and a four-digit number.
CAS Registry Numbers are used extensively in chemistry and commerce to identify chemical substances.
One reason is that CAS Numbers tolerate human data entry errors thanks to a built-in check digit. For example, the CAS number for Imatinib, , contains six digits in the first block, and a check digit of "5".
Also, the attribute can be added to form controls, to programmatically indicate that they are required.
Most current web browsers support this attribute and will communicate missing required input to the user, using standard web browser dialog mechanisms.