On my site designed for mobile devices I have an input field that is used for PIN numbers. I want the text to be hidden as it is entered and I want the number pad to pop up
Why don't you set the input with type="number" and use jQuery to change the type after a keydown in the input.
$("input").keydown(function () {
$(this).prop('type', 'password');
});
Then if you have made a mistake. You could clear the input and set once again the type="number".
$("input").click(function () {
$(this).val('');
$(this).prop('type', 'number');
});
This is my first answer and I hope I've helped.