Question

Using this script:

<script>
$(function() {
    $(window).scroll(function(){
        $('#Your element id').slideUp('slow');
    });
});     
</script>

Is it possible only to perform the action after the user has scrolled 100px or more?

Answer 1

You do need scrollTop as said. It would be wise to include an ‘else’ function as well, so that when you scroll back to the top the toggled element gets hidden again. As such:

$(document).ready(function() {
    $('#scrollDiv').hide();
    $(window).scroll(function() {
        if ($(document).scrollTop() > 100) {
            $('#scrollDiv').fadeIn('slow');
        }
        else {
            $('#scrollDiv').fadeOut('slow');
        }
    });
});​

Here is a quick jsfiddle