Changing input value while still allowing the user to type

Question

Is it possible, using JavaScript or jQuery, to change the content of a text input field while the user types?

E.g. typing a + up would change the

Answer 1

I once had to do a similar thing. I think this is much simpler. Modify it to meet your needs:

$("input#s").keyup(function(e) {
    var m=$("input#s");
    var value= m.val();
    var pos = m.prop('selectionStart');
    value=value.replace(">","»");
    m.val(value);
    m.prop({'selectionStart':pos,'selectionEnd':pos});
});