Scroll down one "scroll unit" on click - javascript

I want to create a link div which scrolls down on click; like one scroll down of the mouse wheel does or one click down on the arrow of the scroll bar.
Is there a method in CSS or jQuery/JavaScript to do that?
And also several scrolls, like 3 scroll downs?
Thanks for help!

As far as I know, there is no such thing as a scroll unit. This is device dependent.
But to make the window scroll when clicking something is simple with jQuery.
$(function(){
$(".clickScroll").click(function(e) {
document.body.scrollTop += 10;
});
});
This will scroll the view 10 units, of some measure, down on every click.
See this plunker for a full example.

You should try something like:
HTML
<div onclick="myFunction()"></div>
JavaScript
myFunction = function(){
var myVar = $(window).scrollTop();
$(window).scrollTop(myVar+300);
}
MyVar gets your position on the page.
I hope I've been helpful.

Related

Adding offset().top amount on scroll

I have a fixed piece of text and I'm trying to add a different class each time the text enters a div on scroll. I've got it working no problem. But if I add an offset amount to the fixed text e.g.
top: 400px
I need to counter this offset in the JS. But I can't seem to figure it out. I've tried using:
.offset().top 400);
But it's not working. Here's a code i'm currently using:
HTML
<p class="text">TEXT HERE</p>
<div class="section1"></div>
<div class="section2"></div>
<div class="section3"></div>
<div class="section4"></div>
JS
$(window).scroll(function (event) {
var scroll = $(window).scrollTop();
$('.text').toggleClass('blue',
scroll >= $('.section1').offset().top
);
$('.text').toggleClass('magenta',
scroll >= $('.section2').offset().top
);
$('.text').toggleClass('green',
scroll >= $('.section3').offset().top
);
$('.text').toggleClass('orange',
scroll >= $('.section4').offset().top
);
});
//trigger the scroll
$(window).scroll();//ensure if you're in current position when page is refreshed
The text needs to add class as soon as it enters the relevant div.
Here's a working fiddle: http://jsfiddle.net/6PrQW/334/
So you did most everything right, but I think where you went wrong is here: var scroll = $(window).scrollTop();
You don't want to calculate using the window offset, rather you want to use the offset of your sticky text. So instead use: var scroll = $('.text').offset().top;
Let me know if that helps.
edit,
and here is your fiddle with the edits.
Note that I edited your line for setting the blue class since you don't want to match the sticky offset against itself.
To find out when something is within your window, you've gotta use something like...
if($(elem).offset().top - $(window).scrollTop < $(window).height()){
//stuff
}
That should trigger as soon as elem is visible on the page! You can check it against $(window).height()/2, for example, if you want it to trigger in the center of the page instead. Hope this helps!

How to stick a div at the bottom of the page while scrolling after checkbox is checked

Usually I don't ask questions...I'm looking for a solution until I give up,
and this is the case here.
There are many similar questions to my but after a thorough search I found nothing.
So the question is:
After selecting a checkbox the div at the bottom of the page
shuold be sticky untill the user scrolling down to the original place where it was.
I have a great example from kickstarter web site :
If only I could know how they do it :)
If I was not clear enough I'd love to explain myself better.
Thanks in advance
After clicking on checkbox,
You can add these CSS lines to div
position:fixed;
bottom:0;
you want to add position: fixed and attach it to the bottom of the container when checked
html
<div class="wrapper">
<input type="checkbox" id="check"/>
<div id="foot"></div>
</div>
js
var check = document.getElementById('check');
var foot = document.getElementById('foot');
check.addEventListener('change', function () {
if (check.checked) {
foot.style.position = 'fixed';
foot.style.bottom = 0;
}
});
fiddle - http://jsfiddle.net/qak2ept6/
EDIT - http://jsfiddle.net/qak2ept6/1/ restore when unchecked
EDIT EDIT - http://jsfiddle.net/qak2ept6/3/ attach on scroll
when you check the check box. create div with position fixed and store the offset of the bottom edge of the window that would be normally your window height. Assign scroll event and keep checking if the scroll value is equal to the offset you have stored and when it reached just remove the fixed position from the div.
My guess (and if I was doing it) It'll be done by monitoring scroll position and applying a css style or not accordingly.
Something like
Inject it in invisible state in to the document
Note it's position (y coord)
Apply class to make it stick to the bottom of the window and show
On scroll, as soon as you get near the expected yCoord, remove the class and let it assume it's rightful place in the document
On further scroll (when you scroll away), re-apply class until you scroll back
HTH
If i have understood your question, I guess what you want is here
function sticky_relocate() {
var window_top = $(window).scrollTop();
var div_top = $('#sticky-anchor').offset().top
if (window_top > div_top) {
$('#sticky').addClass('stick');
} else {
$('#sticky').removeClass('stick');
}
}
$(function () {
$(window).scroll(sticky_relocate);
sticky_relocate();
});
If not, please explain us with more code and what exactly you need

How do I change this script to use a number to show content using JQuery?

This is my code:
$( document ).ready(function() {
var target = $(".passthis").offset().top-$(window).height();
$(document).scroll(function() {
if ($(window).scrollTop() >= target) {
$(".something").fadeIn(2000);
}
});
});
HTML:
<div class="passthis" style="text-align:center;font-size:20px;margin-top:815px;">
Scroll Below here
</div>
Right now this code will show div.something only when the user passes div.passthis. The .passthis div is exactly at the bottom of the screen. Howver, I want to move .passthis the middle of the screen but being new to JS i am unsure how i can modify my script to do that. Can I use a number for x,y or something?
Question:
What can I do to move the .passthis to the middle of the screen and still make .something show after the user passes .passthis.
Here is a jsFiddle demo that you are welcome to play with. As I explained, if the window never scrolls, nothing is going to happen (.something will never appear). Additionally, you can see the numbers for the different values in this demo. It should give you an idea of what you're shooting for as far as the MATH of it all is concerned. As recommended above, you should read up on jQuery's .scrollTop() and other window dimensional methods and values.

Always scroll a div element and not page itself

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

Trigger JQuery function when passed half way down the page

Is there a way to tell if you have scrolled passed the center of the web page or in other words, when you have scrolled passed exactly half of the web page and your scrollbar is situated in the lower half of the browser window?
I want to be able to trigger this:
$('.pineapple-man').show(); when I have scrolled down passed half of the page?
Is this possible at all?
Your help would be so kind!
You can get the pixel amount of an element has been scrolled by using .scrollTop(). To listen to scroll events use .scroll().
When you want to identify the halfway, use height of the scroll:
$(window).scroll(function () {
if ($(window).scrollTop() > $('body').height() / 2) {
$('.pineapple-man').show();
}
});
If you are scrolling some other element than the whole window/body, please feel free to change the selectors.
To make the showing one-timer, add the removal of scroll event listener, by adding the following after the .show() call:
$(window).unbind('scroll');
I guess you want to do something like this:
if($(document).scrollTop() > $(document).height()/2){
$('.pineapple-man').show();
}
where scrollTop() gets the current horizontal position and height() defines the document height.
See the scroll event and the scrollTop method.
you can use the focus event if you scroll down to it (just like jQuery uses for their comments)
jQuery('selector').focus(function() {
jQuery('.page').show();
});

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