Phone mask with jQuery and Masked Input Plugin

You need a jQuery plugin for the mask works as well.

-- HTML --

<input type="text" id="phone" placeholder="(99) 9999-9999">
<input type="text" id="telf1" placeholder="(99) 9999*-9999">
<input type="text" id="telf2" placeholder="(99) 9999?-9999">

-- JAVASCRIPT --

<script src="https://raw.githubusercontent.com/igorescobar/jQuery-Mask-Plugin/master/src/jquery.mask.js"></script>
<script>
$(document).ready(function($){
    $("#phone").mask("(99) 9999-9999"); 
    $("#telf1").mask("(99) 9999*-9999");    
    $("#telf2").mask("(99) 9999?-9999"); 
});
</script>

Actually the correct answer is on http://jsfiddle.net/HDakN/

Zoltan answer will allow user entry "(99) 9999" and then leave the field incomplete

$("#phone").mask("(99) 9999-9999?9");


$("#phone").on("blur", function() {
    var last = $(this).val().substr( $(this).val().indexOf("-") + 1 );

    if( last.length == 5 ) {
        var move = $(this).val().substr( $(this).val().indexOf("-") + 1, 1 );

        var lastfour = last.substr(1,4);

        var first = $(this).val().substr( 0, 9 );

        $(this).val( first + move + '-' + lastfour );
    }
});​

Here is a jQuery phone number mask. No plugin required. Format can be adjusted to your needs.

Updated JSFiddle.

HTML

<form id="example-form" name="my-form">
    <input id="phone-number" name="phone-number" type="text" placeholder="(XXX) XXX-XXXX">
</form>

JavaScript

$('#phone-number', '#example-form')

.keydown(function (e) {
    var key = e.which || e.charCode || e.keyCode || 0;
    $phone = $(this);

    // Don't let them remove the starting '('
    if ($phone.val().length === 1 && (key === 8 || key === 46)) {
        $phone.val('('); 
        return false;
    } 
    // Reset if they highlight and type over first char.
    else if ($phone.val().charAt(0) !== '(') {
        $phone.val('('+$phone.val()); 
    }

    // Auto-format- do not expose the mask as the user begins to type
    if (key !== 8 && key !== 9) {
        if ($phone.val().length === 4) {
            $phone.val($phone.val() + ')');
        }
        if ($phone.val().length === 5) {
            $phone.val($phone.val() + ' ');
        }           
        if ($phone.val().length === 9) {
            $phone.val($phone.val() + '-');
        }
    }

    // Allow numeric (and tab, backspace, delete) keys only
    return (key == 8 || 
            key == 9 ||
            key == 46 ||
            (key >= 48 && key <= 57) ||
            (key >= 96 && key <= 105)); 
})

.bind('focus click', function () {
    $phone = $(this);

    if ($phone.val().length === 0) {
        $phone.val('(');
    }
    else {
        var val = $phone.val();
        $phone.val('').val(val); // Ensure cursor remains at the end
    }
})

.blur(function () {
    $phone = $(this);

    if ($phone.val() === '(') {
        $phone.val('');
    }
});

Try this - http://jsfiddle.net/dKRGE/3/

$("#phone").mask("(99) 9999?9-9999");

$("#phone").on("blur", function() {
    var last = $(this).val().substr( $(this).val().indexOf("-") + 1 );

    if( last.length == 3 ) {
        var move = $(this).val().substr( $(this).val().indexOf("-") - 1, 1 );
        var lastfour = move + last;
        var first = $(this).val().substr( 0, 9 );

        $(this).val( first + '-' + lastfour );
    }
});