因此,我正在使用 Paul Irish 的 requestAnimationFrame 在页面上制作侧边栏“粘性”。我发现至少在 webkit 浏览器中,这比 Waypoints 等其他解决方案带来了巨大的性能改进。但是,我在 Firefox 上注意到,当我开始滚动页面时,CPU 会飞过屋顶,因此页面速度非常慢。我是在执行这个错误,还是需要为 Firefox 使用另一种方法?
(function() {
var lastTime = 0;
var vendors = ['ms', 'moz', 'webkit', 'o'];
for(var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
window.requestAnimationFrame = window[vendors[x]+'RequestAnimationFrame'];
window.cancelAnimationFrame =
window[vendors[x]+'CancelAnimationFrame'] || window[vendors[x]+'CancelRequestAnimationFrame'];
}
if (!window.requestAnimationFrame)
window.requestAnimationFrame = function(callback, element) {
var currTime = new Date().getTime();
var timeToCall = Math.max(0, 16 - (currTime - lastTime));
var id = window.setTimeout(function() { callback(currTime + timeToCall); },
timeToCall);
lastTime = currTime + timeToCall;
return id;
};
if (!window.cancelAnimationFrame)
window.cancelAnimationFrame = function(id) {
clearTimeout(id);
};
}());
window.widget_is_sticky = false;
window.widget_is_locked = false;
$(function(){
(function animloop() {
requestAnimationFrame(animloop);
if (adjust_networth) {
if (self.pageYOffset) {
yScroll = self.pageYOffset;
} else if (document.documentElement && document.documentElement.scrollTop) {
yScroll = document.documentElement.scrollTop;
} else if (document.body) {// all other Explorers
yScroll = document.body.scrollTop;
}
update_networth_position(yScroll);
}
})();
});
// Separate file written in CoffeeScript
window.update_networth_position = ( offset ) ->
if offset >= 259
if !window.widget_is_sticky
window.widget_is_sticky = true
$('.widgets').addClass 'sticky'
else if !window.widget_is_locked and widget_is_at_boundary(offset)
window.widget_is_locked = true
$('.widgets').addClass 'locked'
else if !widget_is_at_boundary(offset) and window.widget_is_locked
window.widget_is_locked = false
$('.widgets').removeClass 'locked'
else
return false if !window.widget_is_sticky
$('.widgets').removeClass 'sticky'
window.widget_is_sticky = false
widget_is_at_boundary = ( offset ) ->
offset = offset - $('section.top-section').outerHeight(true)
maximum_height = $('section.main-content div.content:first-child').outerHeight(true)
widget_height = $('section.main-content .widgets').outerHeight(true)
if (offset + widget_height) > maximum_height
return true
else
return false
非常感谢任何帮助!对于如何解决这个问题,我也对完全不同的解决方案持开放态度(但 Waypoints 的性能不足以很好地工作)。