jQuery disable/enable submit button

Question

I have this HTML:

How can I do something li

Answer 1

you can also use something like this :

$(document).ready(function() {
    $('input[type="submit"]').attr('disabled', true);
    $('input[type="text"]').on('keyup',function() {
        if($(this).val() != '') {
            $('input[type="submit"]').attr('disabled' , false);
        }else{
            $('input[type="submit"]').attr('disabled' , true);
        }
    });
});

here is Live example