How to restrict an input box to accept only alphabets?

INPUT:

<input type="text" class='name' name="first"/>

CODE:

<script>
    $(".name").keydown(function(event)

    {

        if ( $.inArray(event.keyCode,[46,8]) !== -1 || (event.keyCode == 65 && event.ctrlKey === true) || (event.keyCode >= 35 && event.keyCode <= 39))

        {

            return;

        }

        else
        {

            if (event.shiftKey || (event.keyCode < 65 || event.keyCode > 122) && (event.keyCode < 8 || event.keyCode > 32 ))

            {

                event.preventDefault();

            }

        }

    });
</script>

Live Example jsfiddle: https://jsfiddle.net/akhilreddyyalla/o2gxgz9r/46107/