這應該幫助你在正確的方向:
var footer = $("#footer");
// min amount to show when not scrolled to the bottom of the page.
var minVisable = 25;
$(parent.document).scroll(function() {
// check position
if (window.scrollY + window.innerHeight + minVisable > $("html").height()) {
// if at the bottom of the page, stick the footer to it
footer.css("position","absolute").css("top", $("html").height() - footer.height());
} else {
// else keep top part of footer on the screen
footer.css("position","fixed").css("top", window.innerHeight - minVisable);
}
});