A bookmarklet to scroll to the bottom of a webpage - javascript

i wonder if it is possible to create a bookmarklet to click on and the current webpage scrolls to the bottom!
javascript:function%20scrollme(){dh=document.body.scrollHeight;ch=document.body.clientHeight;if(dh>ch){moveme=dh-ch;window.scrollTo(0,moveme);}}
if i create a new bookmark and paste this as address nothing happens. I actually have no idea how to run javascript within a bookmarklet, however i just bookmarked the css-tricks Printliminator
maybe you could help, i would love to have a bookmarklet like this!

First, your JavaScript only defines a function and does nothing else.
Second, you need to use document.documentElement (which represents the <html> element) instead of document.body:
javascript:dh=document.documentElement.scrollHeight;ch=document.documentElement.clientHeight;if(dh>ch){moveme=dh-ch;window.scrollTo(0,moveme);}
or, simply
javascript:window.scrollTo(0,document.documentElement.scrollHeight)
(apparently it doesn't matter if y-coord of window.scrollTo is greater than the maximum position).
Update: In case you have to deal with IE in quirks mode, the root element is indeed document.body. Other browsers let document.documentElement.clientHeight represent the document's height (see Finding the size of the browser window, which deals with the window's height, but contains a nice table). Anyway, you want to set the position of the scroller to whatever is the greatest of the three:
javascript:window.scrollTo(0,Math.max(document.documentElement.scrollHeight,document.body.scrollHeight,document.documentElement.clientHeight))

Here is a function that smoothly scrolls down to the bottom of a page:
function scroll(scroll_to) {
if (scroll.timer) clearTimeout(scroll.timer);
var scroll_current = document.body.scrollTop,
distance = Math.abs(scroll_current - scroll_to);
if (scroll_current == scroll_to) return;
if (scroll_current > scroll_to) {
if (distance < 5) {
scroll_current -= distance;
} else {
scroll_current -= Math.ceil(distance / 10);
}
}
if (scroll_current < scroll_to) {
if (distance < 5) {
scroll_current += distance;
} else {
scroll_current += Math.ceil(distance / 10);
}
}
document.body.scrollTop = scroll_current;
scroll.timer = setTimeout(function() {
scroll(scroll_to)
}, 10);
}
If you call it:
scroll(document.body.scrollHeight - innerHeight);
it will scroll to the bottom of the page.
You can also use it to scroll to the top of the page like this:
scroll(0);
Just attach it to a button or link's onclick event.

you can simply use an anchor with this syntax
<a name="label">Any content</a>
and
Any content

Related

How to know what part of HTML is the user on

so I want to know how I can get what section or part of my html I’m currently on. An example
So how do I know if a user has already scrolled down over part 2 using JavaScript
Or if they’re currently at part 1
<html>
<head>
</head>
<body>
<section class=“part 1”>
</section>
<section class= “part2>
</section>
</body>
</html>
The following codes will give you a little idea about how to handle this situation. Essentially you are going to want to get the scrollbar position which you can do using:
document.documentElement.scrollTop
You also want to get a range where the element you are looking for resides, in our case, it is .part1 and .part2. We can get that range by using offsetTop as the beginning of the limit and offsetTop + clientHeight to determine the end.
You are going to have to keep track of the window scroll event.
The following example is generic:
$(window).scroll(function(e) {
if (document.documentElement.scrollTop > 0
&& document.documentElement.scrollTop < $('.part2').offset().top ) {
$('div').html("At part1")
} else {
$('div').html("At part2")
}
});
JSFiddle
Likewise, if you want a little bit of modularity:
$(window).scroll(function(e) {
let watchList = ['part1', 'part2', 'part3'];
let scrollTop = document.documentElement.scrollTop;
for (var classname of watchList) {
let el = document.getElementsByClassName(classname)[0];
if (scrollTop > el.offsetTop &&
scrollTop < el.offsetTop + el.clientHeight) {
$('div').html("At <strong>"+classname+"</strong>");
}
}
});
JSFiddle
The possibilities are limitless to continue and make this more useful, but I'll leave that up to you.
you can use is[":focus"] function to find which div has focus currently.
if($(".part1").is(":focus"))
{
//you code
}
else if($(".part2").is(":focus"))
{
//you code
}
you can use mouseenter function it fires when the mouse goes into that div for the first time.
$(".part1").on('mouseenter', function(){
//your command
});
you can use mouseover function to find where is mouse right now. it fires when mouse moves inside that div.
$(".part1").on('mouseover', function(){
//your command
});
You can use javascripts offsetTop functionality. This is a parameter that returns how far down from the top a div is in the number of pixels.
It can also return how far down the user has scrolled when called on the window object itself. Then it's just a matter of math. See if the user has scolled down far enough to be past the div in reference.
For example:
var part1DivOffset = document.getElementsByClassName("part 1")[0].offsetTop;
var part2DivOffset = document.getElementsByClassName("part2")[0].offsetTop;
var scrollTop = (window.pageYOffset !== undefined) ? window.pageYOffset : (document.documentElement || document.body.parentNode || document.body).scrollTop;
This code will get you 3 variables. The first 2 lines save the offsetTop of the div's. While the third line detects how far down the user has scrolled. Then you can do math with the variables:
if(scrollTop >= part1DivOffset){
//we are past part1
}
if(scrollTop >= part2DivOffset){
//We are past part 2
}
if(scrollTop >= part1DivOffset && scrollTop < part2DivOffset){
//We are past part 1 but not past part 2
}

Fix header after scrolling Angular 4

I am having issue fixing the header after scrolling, I tried a lot of stuff but can't get it to work. I checked this thread but it doesnt work for me: Angular 4 #HostListener Window scroll event strangely does not work in Firefox . This is my component structure:
Layout
Steps
Routes
Inside steps is my header which I want to fix, after scrolling for 50px. Inside Layout is some other content like a div with logo background (above the content of steps).
This is what I tried inside Steps.ts
#HostListener('window:scroll', [])
onWindowScroll() {
const number = window.scrollY;
if (number > 40) {
this.fixed = true;
} else if (this.fixed && number < 10) {
this.fixed = false;
}
}
but the problem is that scroll is not triggering at all. I found examples
where scroll logs the event, but for me it doesn't work (I tried with $event as well). Anyone has a solution?
Found a solution. On my layout component I put a function
(scroll)="onWindowScroll($event)"
and in layout component i used:
#HostListener('window:scroll', ['$event'])
onWindowScroll($event) {
const number = $event.target.scrollTop;
if (number > 40) {
this.fixed = true;
} else if (this.fixed && number < 10) {
this.fixed = false;
}
}
I removed Steps component since I didnt need it anymore, all the content is inside layout now.
In Angular 5+ it works a little differently:
const number = $event.target.scrollingElement.scrollTop || $event.target.documentElement.scrollTop;
Since some people come via Google to this question:
I'm quite a fan of moving logic like this into something re-useable. For Angular this would mean a directive. Therefore as I run into this issue myself I created a library from my code that at least has some tests and support across many browsers. So feel free to use this tested piece of code instead of polluting your components with more code.
https://w11k.github.io/angular-sticky-things/
With the code I see in the answer I did run into some issues. In another SO I found this solution. It is crucial to determine the offsetY of the header element correctly.
// Thanks to https://stanko.github.io/javascript-get-element-offset/
function getPosition(el) {
let top = 0;
let left = 0;
let element = el;
// Loop through the DOM tree
// and add it's parent's offset to get page offset
do {
top += element.offsetTop || 0;
left += element.offsetLeft || 0;
element = element.offsetParent;
} while (element);
return {
y: top,
x: left,
};

Add class to element if y-position bigger as another element

I want to add a class to an element as soon as the users' scroll-position has "hit" a special - other - element.
I try to use that code therefore
var hands = $(".sw_3--breit");
$(window).scroll(function() {
var scroll = $(window).scrollTop();
// The next line is the one I am asking for help
if (scroll >= window.innerHeight)
{
hands.addClass("fixed");
} else {
hands.removeClass("fixed");
}
});
Which works nice by adding the class after the scroll is bigger then the users display-height I guess. But I want to add - and afterwards also remove - a class when then user has "hit" another element.
What I am asking for is something - very roughly and stupid I know - like:
var other_elements_position = $(".other_element"().position;
if (scroll >= other_elements_position)
How can I achieve that? And I already do use jquery for other things, so using jquery there would make sense I guess.
Thanks!
For people that got the same problem as I do have, this worked for me:
var hands = $(".sw_3--breit");
var hands_original = $(".sw_8").position();
var hands_off = $("#target_agentur").position();
var hands_corrected = (hands_original.top + 680) // here I add a small delay to the trigger of the "animation"
$(window).scroll(function () {
var scroll = $(window).scrollTop();
if (scroll >= hands_corrected && scroll <= hands_off.top) // I doublecheck against 2 heights
{
hands.addClass("fixed");
} else {
hands.removeClass("fixed");
}
});

How can I set my browser window's scrollbar or a div scrollbar to scroll in increments using animate and scrollTop?

The general idea to the site i am designing is to scroll through a set of menu items horizontally and incrementally underneath a static div that will magnify(increase dimensions and pt size) the contents of a menu items. I don't really need help with the magnify portion because i think it's as simple as adding a mag class to any of the menuItem divs that go underneath the static div. I have been messing with this for a few weeks and the code I have for incrementally scrolling, so far, is this:
$(document).ready(function () {
currentScrollPos = $('#scrollableDiv').scrollTop(120); //sets default scroll pos
/*The incrementScroll function is passed arguments currentScrollPos and UserScroll which are variables that i have initiated earlier in the program, and then initiates a for loop.
-The first statement sets up the variables: nextScrollPos as equal to the currentScrollPos(which by default is 120px) plus 240px(the distance to next menuItem), prevScrollPos as equal to the currentScrollPos(which by default is 120px) minus 240px(the distance to next menuItem).
-The second Statement checks to see if the user has scrolled using var userScroll
-The third statement sets: var CurrentScroll equal to the new scroll position and var userScroll to false*/
function incrementScroll(currentScrollPos, userScroll) {
for (var nextScrollPos = parseInt(currentScrollPos + 240, 10),
prevScrollPos = parseInt(currentScrollPos - 240, 10); //end first statement
userScroll == 'true'; console.log('dude'), //end second statement and begining of third
currentScrollPos = scrollTop(), userScroll = 'false') {
if (scrollTop() < currentScrollPos) {
$('#scrollableDiv').animate({
scrollTop: (parseInt(prevScrollPos, 10))
}, 200);
console.log('scrolln up')
} else if (scrollTop() > currentScrollPos) {
$('#scrollableDiv').animate({
scrollTop: (parseInt(nextScrollPos, 10))
}, 200);
console.log('scrolln down')//fire when
}
}
}
$('#scrollableDiv').scroll(function () {
userScroll = 'true';
_.debounce(incrementScroll, 200); //controls the amount of times the incrementScroll function is called
console.log('straight scrolln')
});
});
I have found a variety of solutions that are nigh close: such as a plugin that snaps to the next or previous div horizontally demo, another solution that also snaps and is based on setTimeout demo, but nothing that nails incrementally scrolling through divs. I also found a way to control the rate at which a user may scroll through the menuItems using debounce which is included in the above code.
The console.logs inside the loop do not fire when I demo the code in jsfiddle which leads me to believe the problem lies within the loop. I'm a noob though so it could be in syntax or anywhere else in the code for that matter. Also in the second demo, i have provided the css for the horizontal static div, but the moment I put it in my html it keeps the js from working.
I would like to write the code instead of using a plugin and any help would be appreciated! Also, thank you ahead of time!
Try this fiddle. Menu container height is 960px to show 4 menu items. "Zoom" div is positioned absolutely at top. When you scroll mouse over this div, menu items shifts to top/bottom. I had to add additional div to bottom to be able to scroll to last 3 menu items. JS code:
jQuery(document).ready(function($){
var current = 0;
var menu = $('.menu-container').scrollTop(0);
var items = menu.find('.menu-item');
var zoom = $('.zoom');
function isVerticalScroll(event){
var e = event.originalEvent;
if (e.axis && e.axis === e.HORIZONTAL_AXIS)
return false;
if (e.wheelDeltaX)
return false;
return true;
}
function handleMouseScroll(event){
if(isVerticalScroll(event)){
var delta = event.originalEvent.wheelDelta * -1 || event.originalEvent.detail;
current += (delta > 0 ? 1 : -1);
if(current < 0)
current = 0;
if(current >= items.length){
current = items.length - 1;
}
menu.stop().animate({
"scrollTop": current * 240
}, 300);
items.removeClass('current').eq(current).addClass('current');
event && event.preventDefault();
return false;
}
}
zoom.on({
"MozMousePixelScroll": handleMouseScroll,
"mousewheel": handleMouseScroll
});
});
Hope it will help.

Get divs within viewport inside a wrapper div

Is there a way to get elements which is:
Inside a div with overflow: scroll
Is in viewport
Just like the following picture, where active div (5,6,7,8,9) is orange, and the others is green (1-4 and >10) :
I just want the mousewheel event to add "active" class to div 5,6,7,8,9 (currently in viewport). View my JSFiddle
$('.wrapper').bind('mousewheel', function (e) {
//addClass 'active' here
});
You could do something like this. I would have re-factored it, but only to show the concept.
Firstly I would attach this to scroll event and not mousewheel. There are those among us that likes to use keyboard for scrolling, and you also have the case of dragging the scrollbar. ;) You also have the case of touch devices.
Note that with this I have set overflow:auto; on wrapper, thus no bottom scroll-bar.
With bottom scrollbar you would either have to live with it becoming tagged as in-view a tad to early, or tumble into the world of doing a cross-browser calculating of IE's clientHeight. But the code should hopefully be OK as a starter.
»»Fiddle««
function isView(wrp, elm)
{
var wrpH = $(wrp).height(),
elmH = $(elm).height(),
elmT = $(elm).offset().top;
return elmT >= 0 &&
elmT + elmH < wrpH;
}
$('.wrapper').bind('scroll', function (e) {
$('div.box').each(function(i, e) {
if (isView(".wrapper", this)) {
$(this).addClass('active');
} else {
$(this).removeClass('active');
}
});
});
Note that you should likely refactor in such a way that .wrapper height is only retrieved once per invocation, or if it is static, at page load etc.
Update; a modified version of isView(). Taking position of container into account. This time looking at dolphins in the pool.
»»Fiddle««
function isView(pool, dolphin) {
var poolT = pool.offset().top,
poolH = pool.height(),
dolpH = dolphin.height(),
dolpT = dolphin.offset().top - poolT;
return dolpT >= 0 && dolpT + dolpH <= poolH;
}

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