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){
    $(window).scroll(function() {
      var scrollTop;
        scrollTop = distance;
        scrollTop = 150;
      if($(window).scrollTop() >= scrollTop) {
        if(!($('#mainNav').hasClass('showNav'))) {
      } else {
        if($('#mainNav').hasClass('showNav')) {

    var windowHeight = $(window).height();
    $('.header-image-base').css('height', windowHeight);

When I look in Chrome’s console’s ‘timeline’ panel, and press record, this is what I see:

enter image description here

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.


(archived screenshot)

Link –

Read More:   How to save an image to localStorage and display it on the next page?

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