Javascript scroll function slow, lots of “Timer Fired: onloadwff.js:310” weasel events in Chrome
I’m trying to debug a page which is acting a little slow in Chrome, think it might be an issue with the following javascript code:
$(document).ready(function() {
function navScroll(distance){
$(window).scroll(function() {
var scrollTop;
if(distance){
scrollTop = distance;
}else{
scrollTop = 150;
}
if($(window).scrollTop() >= scrollTop) {
if(!($('#mainNav').hasClass('showNav'))) {
$('#mainNav').addClass('showNav');
}
} else {
if($('#mainNav').hasClass('showNav')) {
$('#mainNav').removeClass('showNav');
}
}
});
}
if($('.header-image-base').length){
var windowHeight = $(window).height();
$('.header-image-base').css('height', windowHeight);
navScroll(windowHeight);
}else{
navScroll();
}
});
When I look in Chrome’s console’s ‘timeline’ panel, and press record, this is what I see:
Any ideas what is happening here? I can’t find any references to this on google and no idea how to remedy it.
Your page is slow most likely because you’re attaching a handler to the window scroll event—this is not a good practice as explained below:
It’s a very, very, bad idea to attach handlers to the window scroll event. Depending upon the browser the scroll event can fire a lot and putting code in the scroll callback will slow down any attempts to scroll the page (not a good idea). Any performance degradation in the scroll handler(s) as a result will only compound the performance of scrolling overall. Instead it’s much better to use some form of a timer to check every X milliseconds OR to attach a scroll event and only run your code after a delay (or even after a given number of executions – and then a delay). (source)
Your screenshot shows that onloadwff.js is located at chrome-extension://hdokiejnpimakedhajhdlcegeplioahd which means it’s part of the LastPass extension — as seen below. So it’s probably not related to your performance issue.
Link – https://chrome.google.com/webstore/detail/lastpass-free-password-ma/hdokiejnpimakedhajhdlcegeplioahd
