How to get the distance from the top for an element?

Question

I want to know how to use JavaScript to get the distance of an element from the top of the page not the parent element.

Answer 1

warning warning warning warning warning warning

"Classic case" - URL "/#about-us" and div with an id of "about-us". In this case, the top position set by default anchor click behavior (So the top is 0 for about-us div). You must prevent default (Or you'll go crazy for why it doesn't work -or- any other code you find out there). More details below under "warning".

1

Less than 30 seconds solution (Two lines of code "hello world"):

get your element:

var element = document.getElementById("hello");

Get getBoundingClientRect ();

The Element.getBoundingClientRect() method returns the size of an element and its position relative to the viewport. https://developer.mozilla.org/en-US/docs/Web/API/Element/getBoundingClientRect

var rect = element.getBoundingClientRect();

Return object:

Dot notation top

var distance_from_top = rect.top; /* 1007.9971313476562 */

Thats it.

2

StackOverflow nightmare 2 - set scroll position to this value

Again "hello world" (8,000 answers out there - 7,999 not working or to complex).

https://developer.mozilla.org/en-US/docs/Web/API/Window/scrollTo

  window.scrollTo({
    top: element.getBoundingClientRect().top,
    behavior: 'smooth'
  });

Add offset value to top if you want (For sticky navbars).

"Hello World" code snippet (Get distance from top viewport + click to scrollTo)

var element = document.getElementById("hello");
var rect = element.getBoundingClientRect();
var distance_from_top = rect.top; /* 50px */
console.log(distance_from_top);

function scrollTovView(){
  window.scrollTo({
    top: distance_from_top,
    behavior: 'smooth'
  });
}

div{
  text-align:center;
  border: 1px solid lightgray;
}

scrollTo to red DIV
50px height

warning

scrollTo "conflict" with main anchor navbars

This trick is very buggy if, for example, you use this URL (ID to anchor URL)(Top is 0 or "get crazy" hh).

www.mysite/about#hello

  window.scrollTo({
    top: element.getBoundingClientRect().top,
    behavior: 'smooth'
  });

For this code to work you should add:

    if (this.hash !== "") {
      // Prevent default anchor click behavior
      event.preventDefault();

Basic example her: https://www.w3schools.com/howto/howto_css_smooth_scroll.asp