jquery: $(window).scrollTop() but no $(window).scrollBottom()_问答_开发者

I want to place an element to the bo开发者_如何学Gottom of the page whenever the user scrolls the page. It's like "fixed position" but I can't use "position: fixed" css as many of my clients' browser can't support that.

I noticed jquery can get current viewport's top position, but how can I get the bottom of the scroll viewport?

So I am asking how to know: $(window).scrollBottom()

var scrollBottom = $(window).scrollTop() + $(window).height();

I would say that a scrollBottom as a direct opposite of scrollTop should be:

var scrollBottom = $(document).height() - $(window).height() - $(window).scrollTop();

Here is a small ugly test that works for me:

// SCROLLTESTER START //
$('<h1 id="st" style="position: fixed; right: 25px; bottom: 25px;"></h1>').insertAfter('body');

$(window).scroll(function () {
  var st = $(window).scrollTop();
  var scrollBottom = $(document).height() - $(window).height() - $(window).scrollTop();

  $('#st').replaceWith('<h1 id="st" style="position: fixed; right: 25px; bottom: 25px;">scrollTop: ' + st + '<br>scrollBottom: ' + scrollBottom + '</h1>');
});
// SCROLLTESTER END //

For the future, I've made scrollBottom into a jquery plugin, usable in the same way that scrollTop is (i.e. you can set a number and it will scroll that amount from the bottom of the page and return the number of pixels from the bottom of the page, or, return the number of pixels from the bottom of the page if no number is provided)

$.fn.scrollBottom = function(scroll){
  if(typeof scroll === 'number'){
    window.scrollTo(0,$(document).height() - $(window).height() - scroll);
    return $(document).height() - $(window).height() - scroll;
  } else {
    return $(document).height() - $(window).height() - $(window).scrollTop();
  }
}
//Basic Usage
$(window).scrollBottom(500);

var scrollBottom =
    $(document).height() - $(window).height() - $(window).scrollTop();

I think it is better to get bottom scroll.

This will scroll to the very top:

$(window).animate({scrollTop: 0});

This will scroll to the very bottom:

$(window).animate({scrollTop: $(document).height() + $(window).height()});

.. change window to your desired container id or class if necessary (in quotes).

try:

 $(window).scrollTop( $('body').height() );

Here is the best option scroll to bottom for table grid, it will be scroll to the last row of the table grid :

 $('.add-row-btn').click(function () {
     var tempheight = $('#PtsGrid > table').height();
     $('#PtsGrid').animate({
         scrollTop: tempheight
         //scrollTop: $(".scroll-bottom").offset().top
     }, 'slow');
 });

// Back to bottom button
$(window).scroll(function () {
    var scrollBottom = $(this).scrollTop() + $(this).height();
    var scrollTop = $(this).scrollTop();
    var pageHeight = $('html, body').height();//Fixed

    if ($(this).scrollTop() > pageHeight - 700) {
        $('.back-to-bottom').fadeOut('slow');
    } else {
        if ($(this).scrollTop() < 100) {
            $('.back-to-bottom').fadeOut('slow');
        }
        else {
            $('.back-to-bottom').fadeIn('slow');
        }
    }
});
$('.back-to-bottom').click(function () {
    var pageHeight = $('html, body').height();//Fixed
    $('html, body').animate({ scrollTop: pageHeight }, 1500, 'easeInOutExpo');
    return false;
});

var scrolltobottom = document.documentElement.scrollHeight - $(this).outerHeight() - $(this).scrollTop();

For an item in my page :

document.getElementById(elementId).scroll(0,
 document.getElementById(elementId).scrollHeight);

function scrollBottum(elementId){
   document.getElementById(elementId).scroll(0, document.getElementById(elementId).scrollHeight);
}

<html><div><button onclick="scrollBottum('myCart')">Click me to scroll</button></div>
<div id="myCart" style="height: 50px; overflow-y: scroll;">
  <div>1: A First ...</div>
  <div>2: B</div>
  <div>3: C</div>
  <div>4: D</div>
  <div>5: E</div>
  <div>6: F</div>
  <div>7: LAST !!</div>
</div>
</html>

i try that and it work very well

scrollrev(){
    let x:any= document.getElementById('chat')
    x.scrollTop = -9000;
  }

i try that code and it work

 // scroll top
 scroll(){
    let x:any= document.getElementById('chat')
    x.scrollTop = 9000;
  }
  // scroll buttom
  scrollrev(){
    let x:any= document.getElementById('chat')
    x.scrollTop = -9000;
  }

This is a quick hack: just assign the scroll value to a very large number. This will ensure that the page is scrolled to the bottom. Using plain javascript: