Simplify jQuery animation with callback

Question

Looking for feedback on how to better improve the code below to simplify the code below.

var animateTop = $('body');
if ($('html').hasClass('lt-ie9')) {
 animateTop = $('html');
}
$('.var').on('click', function() {
 animateTop.animate({
 scrollTop: $('footer').offset().top
 }, {
 queue: false,
 duration: 1500,
 complete: function() {
 if(!$('.foo').hasClass('active')) {
 $('.foo').toggleClass('active');
 $('.bar').slideToggle(); 
 }
 }
}); 
return false;
}); 

Answer 1

Can't really tell what your code does in real life, thus the following optimization/organization might not work. However, following generic tips, here's what I got:

//we can reduce DOM fetching by fetching html first
//caching it as well as other frequently used elements
//assuming that they never change in the course of your page's life
var html = $('html')
 , footer = $('footer')
 , foo = $('.foo')
 , bar = $('.bar')
 , options = {
 queue: false,
 duration: 1500,
 complete: function () {
 if (!foo.hasClass('active')) {
 foo.toggleClass('active');
 bar.slideToggle();
 }
 }
 }
 ;
//then here, we fetch body only when it's not IE9+ thus reducing operations
html = html.hasClass('lt-ie9') ? html : $('body');
$('.var').on('click', function (e) {
 //i think the properties can't be cached since it may need current values
 //however, your options can be cached since they are static values
 html.animate({
 scrollTop: footer.offset().top
 }, options);
 //an answer as to when to use return false vs preventDefault
 //you can use either, depending on the situation
 //http://stackoverflow.com/a/1357151/575527
 return false;
});