Can I change the “justify-content” value depending on the number of elements in the flex container?

Question

I am working on an image gallery on a legacy site. I can\'t use anything other than regular old HTML/jQuery or JS/CSS. I know this would be a lot easier with Bootstrap or so

Answer 1

How about using margin instead of justify-content:space-between to get the spacing?

/* outer container */
.flex-container {
  padding: 24px 0;
  background: white;
  border: solid 1px rgba(0,0,0,.1);
  max-width: 700px; /* or whatever */
  
  /* flex props */
  display: flex;
  flex-wrap: wrap;
  justify-content:center;
}

/* contains img block and title */
.thumb-grid {
  border: solid 1px rgba(0,0,0,.1);
  width: 150px;
  margin: 0 12px 36px;
}

.thumb-grid:first-of-type { margin-left: 0; }
.thumb-grid:nth-of-type(4) { margin-right: 0; }

.thumb-grid p {
  text-align: center;
}

.img-block {
  background: black;
  height: 150px;
}

.img-block img {
  height: 150px;
  opacity: 1;
  transition: opacity 150ms;
}

.img-block:hover img {
  opacity: .9;
}

<div class="flex-container">
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 1</p>      
    </div>
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 2</p>      
    </div>
    
   <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 3</p>      
    </div>
    
    <div class="thumb-grid">
      <div class="img-block">       
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 4</p>      
    </div>
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 5</p>      
    </div>
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 6</p>      
    </div>
    
   <div class="thumb-grid">      
      <div class="img-block">
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 7</p>      
    </div>
    
  </div>

Answer 2

For this layout use CSS grid. Your original problem won't even exist then. You won't need any workaround or hacks, JavaScript, or any weird stuff to make it work. With CSS grid layout you'll easily achieve what you need with elegant and maintainable code.

CSS grid layout is a kind of new CSS feature, and it's actually the first legit way of doing layout, which is awesome. Read about it:

• https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Grid_Layout
• https://css-tricks.com/snippets/css/complete-guide-grid/

For your case, especially take a look at the auto-fill or auto-fit properties. Here's another useful link: https://gridbyexample.com/examples/example37/.

And here's a quick example of what you want to achieve using CSS grid: https://codepen.io/anon/pen/YxbexQ?editors=1100. See how it react to different screen/container width. It just works.

Answer 3

Here is a solution you can use with Flexbox, which will provide a wider cross browser solution than CSS Grid can offer (today).

The main trick is to have ghost elements, 1 less than the amount of items per row.

They take up the same horizontal space as a regular item but have no height, and as such will push any number less than 4 to the left.

As we can use the pseudo elements, we in this case only need 1 extra element acting as a ghost

Stack snippet

/* outer container */
.flex-container {
  padding: 24px 0;
  background: white;
  border: solid 1px rgba(0,0,0,.1);
  max-width: 700px; /* or whatever */
  
  /* flex props */
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
}

/* contains img block and title */
.thumb-grid {
  border: solid 1px rgba(0,0,0,.1);
  width: 150px;
  margin-bottom: 36px;
}

.thumb-grid:empty,               /*  the ghost elements  */
.flex-container::before,
.flex-container::after {
  content: '';
  border: solid 1px rgba(0,0,0,0);
  width: 150px;
  margin-bottom: 36px;
  order: 1;
}

.thumb-grid:first-of-type { margin-left: 0; }
.thumb-grid:nth-of-type(4) { margin-right: 0; }

.thumb-grid p {
  text-align: center;
}

.img-block {
  background: black;
  height: 150px;
}

.img-block img {
  height: 150px;
  opacity: 1;
  transition: opacity 150ms;
}

.img-block:hover img {
  opacity: .9;
}

<div class="flex-container">
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 1</p>      
    </div>
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 2</p>      
    </div>
    
   <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 3</p>      
    </div>
    
    <div class="thumb-grid">
      <div class="img-block">       
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 4</p>      
    </div>
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 5</p>      
    </div>
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 6</p>      
    </div>
    
   <div class="thumb-grid">      
      <div class="img-block">
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 7</p>      
    </div>


   <div class="thumb-grid"></div>

  </div>

---

If it is max 3 items per row, we only need the pseudo elements

/* outer container */
.flex-container {
  padding: 24px 0;
  background: white;
  border: solid 1px rgba(0,0,0,.1);
  max-width: 550px; /* or whatever */
  
  /* flex props */
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
}

/* contains img block and title */
.thumb-grid {
  border: solid 1px rgba(0,0,0,.1);
  width: 150px;
  margin-bottom: 36px;
}

.flex-container::before, .flex-container::after {
  content: '';
  border: solid 1px rgba(0,0,0,0);
  width: 150px;
  margin-bottom: 36px;
  order: 1;
}


.thumb-grid:first-of-type { margin-left: 0; }
.thumb-grid:nth-of-type(4) { margin-right: 0; }

.thumb-grid p {
  text-align: center;
}

.img-block {
  background: black;
  height: 150px;
}

.img-block img {
  height: 150px;
  opacity: 1;
  transition: opacity 150ms;
}

.img-block:hover img {
  opacity: .9;
}

<div class="flex-container">
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 1</p>      
    </div>
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 2</p>      
    </div>
    
   <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 3</p>      
    </div>
    
    <div class="thumb-grid">
      <div class="img-block">       
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 4</p>      
    </div>
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 5</p>      
    </div>    
    
  </div>

---

If it can be a dynamic amount of item, like between 3-5, as long as we don't use fewer than 1 less than the max amount, it will work fine.

/* outer container */
.flex-container {
  padding: 24px 0;
  background: white;
  border: solid 1px rgba(0,0,0,.1);
  max-width: 850px; /* or whatever */
  
  /* flex props */
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
}

/* contains img block and title */
.thumb-grid {
  border: solid 1px rgba(0,0,0,.1);
  width: 150px;
  margin-bottom: 36px;
}

.thumb-grid:empty,               /*  the ghost elements  */
.flex-container::before,
.flex-container::after {
  content: '';
  border: solid 1px rgba(0,0,0,0);
  width: 150px;
  margin-bottom: 36px;
  order: 1;
}

.thumb-grid:first-of-type { margin-left: 0; }
.thumb-grid:nth-of-type(4) { margin-right: 0; }

.thumb-grid p {
  text-align: center;
}

.img-block {
  background: black;
  height: 150px;
}

.img-block img {
  height: 150px;
  opacity: 1;
  transition: opacity 150ms;
}

.img-block:hover img {
  opacity: .9;
}

<div class="flex-container">
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 1</p>      
    </div>
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 2</p>      
    </div>
    
   <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 3</p>      
    </div>
    
    <div class="thumb-grid">
      <div class="img-block">       
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 4</p>      
    </div>
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 5</p>      
    </div>
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 6</p>      
    </div>
    
   <div class="thumb-grid">      
      <div class="img-block">
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 7</p>      
    </div>


   <div class="thumb-grid"></div>
   <div class="thumb-grid"></div>

  </div>

Answer 4

Depending on what you need to support, it might make more sense to use CSS grid layouts (as TylerH pointed out, CSS Grids do not have universal browser support). Check the documentation for further info: https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Grid_Layout

.flex-container {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-gap: 10px;
  grid-auto-rows: minmax(100px, auto);
}

<div class="flex-container">
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 1</p>      
    </div>
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 2</p>      
    </div>
    
   <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 3</p>      
    </div>
    
    <div class="thumb-grid">
      <div class="img-block">       
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 4</p>      
    </div>
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 5</p>      
    </div>
    
    <div class="thumb-grid">      
      <div class="img-block">        
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 6</p>      
    </div>
    
   <div class="thumb-grid">      
      <div class="img-block">
        <a href=""><img src="https://www.expedient.com/wp-content/uploads/2017/06/exp-mq-resouce-thumbnail-1-150x150.jpg" alt="example image"></a>        
      </div>      
      <p>Image 7</p>      
    </div>
    
  </div>