Mask input the phone number JavaScript

Question

I need to develop a pattern of input numbers, must start with a digit 2 and still have 6 digits or begin with "(012)2" and 6 digits, or else as "290-53-21" I made on the number of digits and the starting number 2, and on the dash(-), but I can not do at "(012)" how to write it? My code:

function checkNumber(str){
    if(!str.length)
         alert("error");
     var tmp = new RegExp("(2?|\([032]{3}\)?)[0-9-]{6,9}");
     str = str.replace(tmp, "");
     if(str != "")
         alert("error");
}

Answer 1

This one seems to do the trick:

^(((\(012\))\d|2)\d{6}|2\d{2}(-\d{2}){2})$

It's like this:

• ^ and $ are start and end...
• The regular expression is like this ^( x | y )$
• where x is ((\\(012\\))\\d|2)\\d{6} , this will match (012)d or a 2 with ((\\(012\\))\\d|2) and 6 digits with \\d{6}
• and where y is 2\\d{2}(-\\d{2}){2} , for a 2 followed by 2 digits \\d{2} , and followed by two times -dd (-\\d{2}){2}

Answer 2

var t = /^(?:\(012\))?2(?:\d{6}|\d{2}(?:-\d{2}){2})$/
t.test(2123456); // true
t.test('212-31-23'); // true
t.test('(012)212-31-23'); // true
t.test('(012)2123123'); // true
t.test('(012)212-34-56'); // true

t.test('((012)2123456245-11-11'); // false

Here's how it works:

/^ - indicates the beggining

(?:(012))? - accepts (012) or nothing

2 - the initial 2

(?:A|B) - accepts either 6 digits like so: 'aaaaaa' or 'aa-aa-aa'

where A = \\d{6}

and B = \\d{2}(?:-\\d{2}){2}

Hopefully that helps.