Managing a large web page with extensive JavaScript functionality can be challenging, especially when dealing with fixed position elements that update based on user scroll behavior. A common issue that arises is the noticeable jumping of these elements when scrolling quickly or using the mouse wheel due to delays in executing code related to the scroll event.
To illustrate this issue, you can check out this jsfiddle example: http://jsfiddle.net/jorsgj2b/1/. In this demo, the delay in function execution is simulated using setTimeout.
<div class="header"></div>
<div class="main"></div>
<div class="float"></div>
.header {
width: 100%;
height: 200px;
background-color: #787878;
}
.main {
width: 100%;
height: 1400px;
background-color: lightblue;
}
.float {
position: fixed;
width: 100px;
height: 50px;
top: 233px;
right: 25px;
background-color: red;
z-index: 2;
}
$(function() {
$(window).scroll(function() {
setTimeout(updateFloat, 50);
});
});
var updateFloat = function() {
var mainTop = $('.main').offset().top;
var scrollPos = $(window).scrollTop();
var floatOffset = 25;
var newTop = (scrollPos > mainTop)
? floatOffset + 'px'
: mainTop + floatOffset - scrollPos + 'px';
$('.float').css('top', newTop);;
}
Dealing with this issue can be tricky. Some attempted solutions include updating margins instead of top positions and switching between absolute and fixed positioning. Utilizing CSS transitions could potentially offer a workaround, but implementation may vary depending on the specific scenario.