How to Know Which HTML Element is Causing Vertical Scroll Bar

html

responsive-design

css-selectors

debugging

byAlex Kataev·Dec 5, 2024

To swiftly identify the elusive rogue known as the vertical scrollbar, take advantage of the power vested in Chrome DevTools. Swing into action by pressing the mighty F12, then advance to the Elements pane. Incant the spell overflow: hidden; onto the elements within the mystical Styles section. Upon the scrollbar's disappearance, the final modified element is your perpetrator. Here's the magic phrase:

/* Apply to potential culprits */
.element { overflow: hidden; }

Discerning the culprit with CSS

A great first technique is to use CSS to highlight every element. Think of this as casting a wide net over every possible suspect. Try out this code:

/* The Red Outline of Judgement */
* { outline: 1px solid red; }

This won’t mess with the layout but will illustrate which block is acting a bit too big for its boots, i.e., the one crawling out of your viewport.

Using JavaScript to detect culprits

Sometimes you need to whip out the big guns - or JavaScript in this case. By implementing the function below, JavaScript can take on the role of detective, inspecting each element for signs of mischief:

function findScroller(element) {
  /* Any scrollHeight boasting beyond its clientHeight is suspicious */
  if (element.scrollHeight > element.clientHeight) {
    console.log(element);
  }
  /* The child elements won’t get away, we’re checking you one by one! */
  Array.from(element.children).forEach(findScroller);
}

findScroller(document.body);

Inspecting external content: iframes and off-screen elements

IFrames and elements chilling off-screen are notorious scrollbar provocateurs. Be thorough and check these fellows by setting display: none; or delete them temporarily from your HTML structure. If the scrollbar exits the scene, you've found your perp!

/* Whistle nonchalantly while turning off visibility */
iframe, .offscreen-element { display: none; }

Playing it safe with padding instead of margins

Margins can be troublemakers due to collapsing margins. Using padding-top instead of margin-top however, makes your layout more predictable and less prone to sudden, mystifying scrollbars:

/* Pandemonium? Nah. Padding-top! */
.nav-adjustment { padding-top: 20px; }

Highlighting using Chrome

Are you a visual debug person? Try highlighting each element one by one using Chrome DevTools.

Angling with CSS selectors

The simplest solution is often the best. You can target your suspects directly using specific CSS selectors:

/* A good old CSS sting operation */
#content, .main, .wrapper { overflow: hidden; }

Interpreting margin collapse and padding

Understanding the intricacies of margin collapse and padding is crucial to grasp why some elements break your layout. Knowledge is power!

Employing Array.from() and Event Listeners with JavaScript

Capture the scrollbar bandit by setting up a stakeout! Use Array.from() and Event Listeners to keep track of any size modifications and apprehend the element causing trouble.