What is the right way to build simple floating divs using Javascript (or CSS programmatically)
that is on top and always visible when scrolling down?
Now I've seen examples like this. When you scroll down you see the div jumping and a delay. I want it to constantly be on top when the content of the page is not my ,
the script will be injected via chrome extention
can it be done?
something like this ; but less complex and not depend on the page content
With the class or id of the element you want to keep on top you should apply some CSS rules,
for example, if your element class is .topnavigation
you could do the following in jQuery
<style>
.topnavigation {
width:;/* add the width here */
position:static;
}
.topnavigation.scrolling {
position:fixed;
top:0px;
}
</style>
<script>
$(window).scroll(function () {
if($(this).scrollTop() > 50) // change 50 to what you want (work out how far the nav is from the top of the page alraedy and add it there, that'll make it smoother transition)
{
$('.topnavigation').addClass('scrolling');
} else {
$('.topnavigation').removeClass('scrolling');
}
});
</script>
If you can't use jQuery you could do the following with normal javascript:
Updated: 06 Jan 2017
I've updated this to use the document.querySelector and Element.classList methods. All modern browsers and IE 10 > support these methods.
window.addEventListener('scroll',checkPosition,false);
function checkPosition()
{
// #theid or #theclass or standard element selector
var xNAV = document.querySelector("#topnav");
if(window.scrollY > 50)
{
xNAV.classList.add("scrolling");
} else {
xNAV.classList.remove("scrolling");
}
}
With JavaScript, determine when you want it to be floating, then add css: position:fixed
Related
I have a fixed header with :target in-page anchors, and need to adjust the property values dynamically via JavaScript or JQuery so as to maintain the relevant :target's position directly under the header when the window is resized, while adapting to the changes in both the previous section's .container height and the .header_container height that occur with resizing.
The simplest solution seems to be a ::before pseudo-element for the :target pseudo-class, and to then utilize CSS custom properties to dynamically modify the style properties.
I have no trouble correctly positioning the :target with the below function when the page is loaded (or reloaded), or correctly position the first :target on $(window).resize(), however it's failing to do the same for the remaining targets on $(window).resize().
Fiddles
Simplified Code: https://jsfiddle.net/chayanyc/g6p3549s/
Responsive Design (Simplified): https://jsfiddle.net/chayanyc/wuk92dns/
Code Snippets
CSS:
.header_container {height: 98px; margin: 0; padding: 0; position: fixed; top: 0; display: block; z-index: 100;}
.main {margin-top: 98px; width: 100%;}
:target::before {height: var(--target_position1); margin-top: var(--target_position2); content: ""; display: block; visibility: hidden;}
JavaScript:
var headerHeight;
function setTarget() {
headerHeight = document.getElementById('header').offsetHeight;
headerHeight1 = headerHeight + "px";
document.documentElement.style.setProperty('--target_position1', headerHeight1);
document.documentElement.style.setProperty('--target_position2', '-' + headerHeight1);
}
$(window).resize(function () {
setTarget();
});
$(document).ready(function () {
setTarget();
});
There is no complete solution to this Problem,
because you want the target element stay on place on document resize, but if the user do a scroll on his page, it is not possible to know where staying on the same first word of the first line on display.
So here, i just replace on the same target on top when user resize his document, even if he had done a scroll just before.
no need of this CSS part (remove it)
:target::before {margin: 0; content: ""; dis.....
and change your jQuery to:
$(document).ready(function () {
// global info for menu -> target elememt
var InfoTarget = { ID: null, tempo:300 }
$('a').click(function(evt){
InfoTarget.ID = $(this).attr('href') // possible target elm
// check if InfoTarget.ID exist on page
let nbElements = 0
try { nbElements = $(InfoTarget.ID).length }
catch(err) { nbElements = 0 }
if ( nbElements != 1 ) {
InfoTarget.ID = null // not target element found
}
else {
evt.preventDefault() // disable auto scroll to target element
$('html').animate({
scrollTop: ($(InfoTarget.ID).offset().top - $('#header').outerHeight(true))
}, InfoTarget.tempo );
}
});
$(window).resize(function (){
if (InfoTarget.ID) { // if InfoTarget.ID exist <=> InfoTarget.ID != null
$('html').animate({
scrollTop: ($(InfoTarget.ID).offset().top - $('#header').outerHeight(true))
}, InfoTarget.tempo);
}
});
});
My code speaks for itself, but here is a complete explanation:
the principle is simple: the function target css activates on a click on a link <a href="#..."> to trigger a scroll of the page towards the element having for id = to that contained in the initial href.
therefore this code intercepts any click on a link on the page and must first determine whether it is a link to an anchor or not.
To determine if this is a link to an anchor on the page, it simply tests whether an element of the page has this value as this ID, (// check if InfoTarget.ID exists on page).
As this kind of test can also generate an error, this test is placed in a try / catch.
If the result is indeed an anchor, then the action of the click is canceled, (with evt.preventDefault()) which prevents the browser from triggering its automatic scroll to the link;
the reference link is kept in an object variable (global)
var InfoTarget = {ID: null, tempo: 300}
seen on: InfoTarget.ID = $(this).attr('href') // possible target elm
the rest is simple, you have to scroll down to the anchor.
Depending on the width of the page and the previous elements, browsers continuously recalculate the position of each tag present on a page and jQuery can be retrieved this offset position by $(element).offset().Top
as there is a menu bar on your page that masks the top of the page, you must deduct its height from the position in scroll (= $ ('# header'). outerHeight (true))
a scroll = 0 will force a move to the top of the page
a scroll = $(element).offset().top places the element at the top of the page
to which we must deduct the height of the #header
the complete formula is
scrollTop: ( $(InfoTarget.ID).offset().top - $('#header').outerHeight(true) )
this command is placed in a jQuery.animate, for a visually smoother move, and uses the InfoTarget.tempo value as the duration for this animation.
During a resize of the page, and to the extent that a link having a target has been previously clicked (therefore always active) then the same type of scroll is triggered.
The different jQuery methods used are all explained in the jQuery doc (for example: https://api.jquery.com/outerHeight/ )
New Solution -- Lundi 14 oct 2019 / 01:00 (in the night of sunday / monday)
this script must be placed after all the html elements of the body
// scroll to target upon window.location.hash
$(window).on('hashchange', function() {
$('.TargetMark').removeClass('TargetMark')
$(window.location.hash).addClass('TargetMark')
setTimeout( scrollTop2, 220 ) // scroll to target after browser auto scrolling conflit
})
function scrollTop2() {
if ($('.TargetMark').length===1) { // if target exist
$('html').animate({
scrollTop: ($('.TargetMark').offset().top - $('#header').outerHeight(true))
}, 100);
}
}
In this version the target element is added a class (TargetMark) allowing to find it when window resize
ending part
$(document).ready(function () {
//...
// ---------------------------> no call to scrollTop();
//...
});
$(window).resize(function () {
//...
scrollTop2();
//...
});
about toggleMenu conflict:
function toggleMenu() {
$('.navbar-toggle').on('click', function () {
if ($("#js-menu").is(".expand")) {
$("#js-menu").toggleClass("expand");
$("#submenu").removeClass("active_sub").addClass("inactive_sub");
} else {
$("#js-menu").toggleClass("expand");
$("#submenu").removeClass("inactive_sub").addClass("active_sub");
}
resetTarget();
setTimeout( scrollTop2, 220 ) // scroll to target after browser auto scrolling conflit
});
}
I spent a lot of my time on your question, I studied differents approaches and the different automatisms put at work by the navigators themselves and which is necessary to fight to get the result you'r looking for. I came to the conclusion that the problem first came from the architecture of your page.
The fact that the menu ("#header") covers the page ("#main") is a major flaw that prevents to have an effective JS code for your question.
The call on the hash of an anchor triggers one or more scrolls of the page, the resize of the page also entails a scroll calculation because by changing size on the screen, it also changes the size of the page. page (reducing the size of the screen by half makes the page size double), it is the same by changing the size of the font, it also changes the size in page.
Whenever the page size changes, the browser must recalculate a lot of things and some of these mechanisms can trigger one or more scrolls.
What you are asking here is to recalculate a page positioning according to an element of which we can not be certain that it is completely established because this process is executed in parallel with other processes of the browser which can change useful values.
Plus the fact that some of the browser processes also work to scroll the page and that it can be the last done!
So the fact that there is an overlap between the menu and the page add more complexity and makes the possibility of a solution impossible.
Change your layout and 3/4 of your problem will be fixed.
Resize is firing, offset height is not changing. Setting the same value over and over again, yields no change. You might check this:
see the value change
I used the logo for output:
$('.logo').text(headerHeight + ' -' + i++);
You want to scroll down to the one div selected by target without having it to be overlapped by your nav?
.. then extend the areas. see here
add positive margin-top and negative padding-top.
.... to compensate for any nav size changes, use media queries to change your css vars.
I'm fixing my nav to the top of the page. I'm using Bootstrap (CSS only). I'm using jQuery to hide one logo (img class .logo) and show another (img class .logo-sm), on scroll.
Everything basically works, except for one thing. The hiding function slides the main logo to the left as it fades out, but I'd like it to slide up. I'm pretty sure this is not .hide() function's default behavior, but I don't know jQuery very well so I'm not sure how to change it.
I built a JSFiddle to demonstrate the behavior. It doesn't work consistently for some reason (it does locally), but you can see the logo sliding left the first time you scroll down.
JSFiddle
The script:
$(document).ready(function() {
// nav fixing
$(window).scroll(function() {
if ($(this).scrollTop() > 1){
$(".logo").hide(100);
$(".logo-sm").show(200);
} else {
$(".logo").show(100);
$(".logo-sm").hide(200);
}
});
});
This is happening because .show() is applying display: inline-block when what you need is display: block.
To fix this, you need to find what's setting the header .logo css display value to be inline and change it to block. From the jquery api, show will set the display property to whatever it was set to initially. In this case, it's inline-block which is why your logo is moving to the left.
$.hide() only sets the display of the element to none. It doesn't animate. That behavior is probably caused by having transitions in your CSS.
If you want to animate the element with jQuery, you can use .slideUp() and .slideDown().
$(document).ready(function() {
// nav fixing
$(window).scroll(function() {
if ($(this).scrollTop() > 1){
$(".logo").slideUp(100);
$(".logo-sm").slideDown(200);
} else {
$(".logo").slideUp(100);
$(".logo-sm").slideDown(200);
}
});
});
But you've got some other stuff going on in your fiddle that is causing some weirdness so this won't work much better. I would suggest not animating with jQuery, but use it to change classes on the elements and handle the animation with CSS transitions. Something like this:
$(document).ready(function() {
// nav fixing
$(window).scroll(function() {
if ($(this).scrollTop() > 1){
$(".logo").removeClass("showing");
$(".logo-sm").addClass("showing");
} else {
$(".logo-sm").removeClass("showing");
$(".logo").addClass("showing");
}
});
});
And then style the .showing class with transitions.
The code below is test code I'm using. The blue bar is supposed to stick to the top of the screen when it reaches the top.
This works on my browser, but the reason I'm here is because when it sticks to the top, it all of a sudden becomes smaller. As you see the blue bar starts with a full width across the container, but on my computer/browser, after it sticks to the top, the div shrinks to just the size of the text.
To make matters worse, I cannot reproduce the problem on jfiddle, because in jfiddle it doesn't work at all! (The images are just there to create a scroll).
Here is the jfiddle
Here is the jquery:
var titlePosition = $('.title').offset().top;
$(window).scroll(function () {
var scrollBar = $(this).scrollTop();
if (scrollBar > titlePosition) {
$('.title').css("top", "0px");
$('.title').css("position", "fixed");
} else {
$('.title').css("position", "relative");
}
});
Try this code:
Fiddle
CSS:
.title {
font-size:200%;
background-color:blue;
width:100%
}
Update your code:
if (scrollBar > titlePosition) {
$('.title').css("top", scrollBar+"px");
$('.title').css("position", "fixed");
} else {
$('.title').css("position", "static"); //otherwise it will still get that top value and cause unwanted position;
}
Just add this css:
.title {
...
width: 100%; /*This does the trick*/
}
Here you have it working: http://jsfiddle.net/edgarinvillegas/yPWAC/3/
Cheers
Set left to 0 as well. Additionally, some optimizations.
I prefer appending/removing classes to put all your CSS in your stylesheet. Saves you from problems later on when the code gets huge (who would be looking for CSS in JS files anyway?).
Also, cache objects. Everytime you fire scroll, your code fetches every single .title in the DOM and generates a jQuery object. Not very optimal. Instead, get all .title and just do the modifications on each scroll.
CSS:
.title.fixed {
position:fixed;
left:0;
right:0;
top:0;
}
JS:
var titlePosition = $('.title').offset().top;
var win = $(window);
var title = $('.title');
win.scroll(function () {
var scrollBar = win.scrollTop();
if (scrollBar > titlePosition) title.addClass('fixed');
else title.removeClass('fixed');
});
As for your non-working fiddle, you forgot to include jQuery. That should be found on the top left.
Try giving z-index:999 or, using jQuery - $('.title').css("z-index", "999");
Rest looks ok.
var titlePosition = $('.title').offset().top;
.top is not a function. offset() returns an object containing the properties top and left
Replace with:
var titlePosition = $('.title').offset();
You can now access the properties like so:
titlePosition.top or titlePosition.left
reference: .offset() http://api.jquery.com/offset/
Thanks for all the feedback.
Even though it helped improve, in the end the div was still resizing. Fixing the width to specific values was not responsive enough.
I finally stumbled upon a solution, based on all the advice:
http://jsfiddle.net/yPWAC/8/
var titleWidth = $('.title').width()
/*then after the div is fixed I change the width */
$('.title').css("width",titleWidth);
I made jquery hold the original width of the div, then change the width of the sticky div to whatever that value is.
For some reason, even if I defined the original width in CSS, the new sticky width would still come out a different size in the browser. So this method gives it the same width as the original (whatever it may be)
I have built a parallax scrolling intro for a clients website - the site contains many high res images - so I have created a quick loader which blanks out the screen with a full screen high z-index div and then uses the setTimeout method to fade in the page 4 seconds after document ready (not sure if this is the best way to do this but it works in every test I've tried).
I would like to disable the scroll to prevent users scrolling through the animation before it appears -can anyone recommend a good cross-browser method to do this?
If you want to fade in when all images are loaded, you can try this
var images = $('img');
var images_nbr = images.length;
images.load(function() {
images_nbr--;
if (images_nbr == 0) {
$('body').css('overflow','auto');
$('...').fadeIn();
}
});
Set
#mydiv {
overflow:hidden
}
in your parent div in CSS. Then, in your document, add this...
$('#mydiv').css('overflow', 'auto');
...in the function that fades in your content.
Thus, on load the page will be unscrollable, but when you fade in, the overflow property will be overwritten and allow the content to scroll.
.scrolldiv{
overflow:hidden;
}
$(window).load(function(){
$(".scrolldiv").css("overflow","auto");
});
You can try like,
initially add the below css on body
body {overflow:hidden;}
and after your setInterval function complete execution (whatever your loading function) just remove the style from body, like
$('body').css('overflow','auto');
I have a page layout with an inner <div id="content"> element which contains the important stuff on the page. The important part about the design is:
#content {
height: 300px;
width: 500px;
overflow: scroll;
}
Now when the containing text is larger than 300px, I need to be able to scroll it. Is it possible to scroll the <div>, even when the mouse is not hovering the element (arrow keys should also work)?
Note that I don’t want to disable the ‘global’ scrolling: There should be two scrollbars on the page, the global scrollbar and the scrollbar for the <div>.
The only thing that changes is that the inner <div> should always scroll unless it can’t be moved anymore (in which case the page should start scrolling).
Is this possible to achieve somehow?
Edit
I think the problem was a bit confusing, so I’ll append a sequence of how I would like it to work. (Khez already supplied a proof-of-concept.)
The first image is how the page looks when opened.
Now, the mouse sits in the indicated position and scrolls and what should happen is that
First the inner div scrolls its content (Fig. 2)
The inner div has finished scrolling (Fig. 3)
The body element scrolls so that the div itself gets moved. (Fig. 4)
Hope it is a bit clearer now.
(Image thanks to gomockingbird.com)
I don't think that is possible to achieve without scripting it, which could be messy, considering the numerous events which scroll an element (click, scrollwheel, down arrow, space bar).
An option could be using the jQuery scroll plugin. I know it has the availability to create scrollbars on an div. The only thing you need to add yourself is the logic to catch the events when keyboard buttons are pressed. Just check out the keycodes for the arrow keys and make the div scroll down.
The plugin can be found here.
You can use it like this;
<script type="text/javascript">
// append scrollbar to all DOM nodes with class css-scrollbar
$(function(){
$('.css-scrollbar').scrollbar();
})
</script>
here is a solution that might work: (fiddle: http://jsfiddle.net/maniator/9sb2a/)
var last_scroll = -1;
$(window).scroll(function(e){
if($('#content').scrollTop());
var scroll = $('#view').data('scroll');
if(scroll == undefined){
$('#content').data('scroll', 5);
scroll = $('#content').data('scroll');
}
else {
$('#content').data('scroll', scroll + 5);
scroll = $('#view').data('scroll');
}
/*
console.log({
'window scroll':$('window').scrollTop(),
'scroll var': scroll,
'view scroll':$('#view').scrollTop(),
'view height':$('#view').height(),
'ls': last_scroll
});
//*/
if(last_scroll != $('#content').scrollTop()){ //check for new scroll
last_scroll = $('#content').scrollTop()
$('#content').scrollTop($('#content').scrollTop() + scroll);
$(this).scrollTop(0);
//console.log(e, 'scrolling');
}
})
It is a bit buggy but it is a start :-)
The only way I believe you can achieve this is through the use of frames.
Frames - W3Schools Reference
If you just want to have a fixed positioned "div" and scroll only it, maybe you could use a trick like:
http://jsfiddle.net/3cpvT/
Scrolling with mouse wheel and all kinds of keys works as expected. Only thing is that the scrollbar is on the document body only.
I found a solution... Not perfect... http://jsfiddle.net/fGjUD/6/.
CSS:
body.noscroll {
position: fixed;
overflow-y: scroll;
width: 100%;
}
JS (jQuery):
if ($("body").height() > $(window).height()) {
var top;
$('#scrolldiv').mouseenter(function() {
top = $(window).scrollTop();
$('body').addClass('noscroll').css({top: -top + 'px'});
}).mouseleave(function() {
$('body').removeClass('noscroll');
$(window).scrollTop(top);
});
}
The text wrapping problem can be solved putting the whole content in fixed-width div. There is another bug for IE browser. If the page has center-aligned backgrond, it will move left-right on mouseenter on #scrolldiv