Question

HOWTO?

show submit button only if one or two needed inputs are filled with a value
but if you remove on of the needed values, the submit has to disappear.

should be done with keyup i think.
any idea?

Answer 1

The function below should help you out:

$(function(){
    // Hide submit button if either field is empty
    $('form input').keyup(function(){
        if($('#input1').val() == "" || $('input2').val() == ""){
            $('#submit').hide();
        }
        else {
            $('#submit').show();
        }
    });
    // Don't submit form if either field is empty
    $('form').submit(function(){
    if($('#1').val() == "" || $('#2').val() == ""){
        return false;
    }
    });
});

By the way, you’ll need to use CSS (display:none) to hide your submit button initially.