Show "back_to_top" when page is scrolled. Go back to "this_is_top" when clicked.
$(document).ready(function() {
var offset_h = 250, duration = 450;
$(window).scroll(function() {
$('#back_to_top').delay(1500).css( "display", "inline" ).fadeOut(1400);
});
$('#back_to_top').click(function(event) {
event.preventDefault();
$('html, body').animate({
scrollTop: $('#this_is_top').offset().top - 220
}, duration);
return false;
});
$('#jump_to_section_3').click(function() {
$('#thankyou_modal').modal('hide');
$('html, body').animate({
scrollTop: $('#third').offset().top - 120
}, 2000);
});
});