JAVASCRIPT

how to check element is in viewport

function isVisible (ele) {
  const { top, bottom } = ele.getBoundingClientRect();
  const vHeight = (window.innerHeight || document.documentElement.clientHeight);

  return (
    (top > 0 || bottom > 0) &&
    top < vHeight
  );
}

how to check if element is in viewport

function isInViewport(element) {
    const rect = element.getBoundingClientRect();
    return (
        rect.top >= 0 &&
        rect.left >= 0 &&
        rect.bottom <= ((window.innerHeight + rect.height) || document.documentElement.clientHeight) &&
        rect.right <= (window.innerWidth || document.documentElement.clientWidth)
    );
}

//optimized from the stackOverflow answer to account 
//for element heights and widths (in vertical/horizontal scrolling)

how to check if element is in viewport javascript

function elementInViewport(el) {
  let top = el.offsetTop;
  let left = el.offsetLeft;
  let width = el.offsetWidth;
  let height = el.offsetHeight;

  while(el.offsetParent) {
    el = el.offsetParent;
    top += el.offsetTop;
    left += el.offsetLeft;
  }

  return (
    top >= window.pageYOffset &&
    left >= window.pageXOffset &&
    (top + height) <= (window.pageYOffset + window.innerHeight) &&
    (left + width) <= (window.pageXOffset + window.innerWidth)
  );
}

how to detect if a particular html element is on viewport or not using javascript

// The following function can be used to check if an element is in the viewport or not if the element is in the viewport this function will return true else it will return false
// this function is taken from: https://www.javascripttutorial.net/dom/css/check-if-an-element-is-visible-in-the-viewport/
function isInViewport(element) {
    const rect = element.getBoundingClientRect();
    return (
        rect.top >= 0 &&
        rect.left >= 0 &&
        rect.bottom <= (window.innerHeight || document.documentElement.clientHeight) &&
        rect.right <= (window.innerWidth || document.documentElement.clientWidth)
    );
}