Set the grid container height as two child items

Question

Is there a chance I can set the grid container's height equal to two grid items using CSS? The attached picture shows the expected result of having the rest of the content set as an overflow scroll.

PS. This shall also be responsive and adjust if the grid container's children's height changes.

userurKQ · Answer

You have to use Javascript for this. Capture the height using the getBoundingClientRect() and the container margin using getComputedStyle(). You have to be a little bit careful how you style the parent and children elements and also be aware of collapsing margins if you use margin-top and margin-bottom. We can then use a CSS variable to store the result and that will then affect the container height rule. We attach the function to the window resize event and also fire it on initial window load. Here's an example to get you started and tweak to suit your needs.

window.onload = () => {
  window.onresize = (event) => {
    resizeContainer();
  };
  resizeContainer();
}

function resizeContainer() {
  const container = document.querySelector('.container');
  const containerStyle = window.getComputedStyle(container);
  const containerPaddingTop = parseInt(containerStyle.getPropertyValue('padding-top'));
  const containerPaddingBottom = parseInt(containerStyle.getPropertyValue('padding-bottom'));
  const child1 = document.querySelector('.container > div:first-child');
  const child2 = document.querySelector('.container > div:nth-child(2)');
  const height = getOverallHeight(child1) + getOverallHeight(child2) + containerPaddingTop + containerPaddingBottom;
  container.style.cssText = "--container-height:" + height + "px";
}

function getOverallHeight(element) {
  const height = element.getBoundingClientRect().height;
  const style = window.getComputedStyle(element);
  const marginTop = parseInt(style.getPropertyValue('margin-top'));
  const marginBottom = parseInt(style.getPropertyValue('margin-bottom'));
  return height + marginTop + marginBottom;
}

* {
  box-sizing: border-box;
}

.container {
  overflow-y: auto;
  height: var(--container-height);
  border: 2px solid black;
  padding: 0.5rem;
}

.container>div {
  border: 2px solid red;
  margin-top: 0.25rem;
  min-height: 5rem;
}


  
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Set the grid container height as two child items

1 Answers