Telephone input mask

[phppup]

I want to use a particular input for telephone numbers.

I have seen working examples, and either need to edit or create code for my end result 

Aside from the usual telephone number mask, this input field dynamically replaces the value/placeholder that is visible.

To elaborate, the user sees the input text box with (___)___-____ displayed.

As digits are entered, the field replaces underscores with digits in a progression until complete.

(21_)___-____ , next (212)55_-____, then (212)555-12__ until finally (212)555-1212

Any direction would be helpful.

Edited June 1, 2019 by phppup

[Barand]

Something like this?

<input type="text" name="phone" id="phone" value="(___) ___ - ____" >

and

        $("#phone").keydown( function(e) {
            var output = $("#phone").val()
            if (output == '') output = "(___) ___ - ____"
            if (output.indexOf('_') != -1) {
                e.preventDefault()
                if (48 <= e.keyCode && e.keyCode <= 57) {         // keyboard top row
                    output = output.replace('_', e.keyCode-48)
                }
                else if (96 <= e.keyCode && e.keyCode <= 105) {   // numeric keypad
                    output = output.replace('_', e.keyCode-96)
                }
                $("#phone").val(output)
            }
       })

 

[phppup]

Something like that. Thanks for the starting point.