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javascripthtmlcss

dropdown menu does not fit in the container when opened

I have got follow html:

nav {
  width: 100px;
}


.nav-menu {
  background-color: orange;
}

.dropdown {
  position: relative;
}


a[data-toggle="dropdown"] {
  display: flex;
  align-items: center;
  background: transparent;
  color: blue;
  padding: 10px 15px;
  border-radius: 4px;
  transition: background 0.3s ease;
  white-space: nowrap;
}

a[data-toggle="dropdown"]:hover {
  color: black;
}

.nav-menu {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  list-style-type: none;
  padding: 0;
  margin: 0;
  align-items: center;
  width: 100%;

}

.dropdown-menu {
  list-style: none;
  padding: 10px 15px;
  margin: 0;
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 200px;
  background: #ffffff;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.15);
  border-radius: 6px;
  overflow: hidden;
  transform: scaleY(0);
  transform-origin: top;
  opacity: 0;
  transition: transform 0.3s ease, opacity 0.3s ease;
  z-index: 1000;
}

.dropdown-menu.show {
  transform: scaleY(1);
  opacity: 1;
}

.dropdown-menu:before {
  display: block;
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  clip-path: inset(0 0 0 0);
}
<nav>
  <ul class="nav-menu">

    <li class="dropdown">
      <a href="#" data-toggle="dropdown">About</a>
      <ul class="dropdown-menu">
        <li><a href="/foo.html">Foo</a></li>
        <li><a href="/bar.html">Bar</a></li>
        <li><a href="/bar.html">Some long text here</a></li>
      </ul>
    </li>

  </ul>
</nav>

But I want to make menu be shown no wider than the dimensions of the container (orange color). The menu must always fit into the container.

menu tears apart the container

https://jsfiddle.net/Suliman123/8tg67sq4/

If menu is longer that container text menu it's text should be fully displayed. In my case there is a lot of menu items. And if no space from right it always have space from left.

Here is illustration: https://jsfiddle.net/Suliman123/Lno7a5p0/ menu here should not be bigger than black region.

Solution

  • We use offsetWidth property in JS to calculate the width of the button - then the event listener in js will apply this width to the dropdown using style.width property.

    You need to make these changes in CSS in the .dropdown-menu:

    width: auto;
min-width: unset;

    This will remove any preset width or min-width in the CSS and will let the JS add on to your CSS.

    This will be your updated JS:

    document.querySelectorAll('.dropdown').forEach((dropdown) => {
  const button = dropdown.querySelector('a[data-toggle="dropdown"]');
  const menu = dropdown.querySelector('.dropdown-menu');

  button.addEventListener('click', (event) => {
    event.preventDefault();
    document.querySelectorAll('.dropdown-menu.show').forEach((openMenu) => {
      if (openMenu !== menu) {
        openMenu.classList.remove('show');
      }
    });
    const buttonWidth = button.offsetWidth;
    menu.style.width = `${buttonWidth}px`;
    menu.classList.toggle('show');
  });
});

// to close the dropdown when clicked anywhere else on the page
document.addEventListener('click', (event) => {
  if (!event.target.closest('.dropdown')) {
    document.querySelectorAll('.dropdown-menu.show').forEach((menu) => {
      menu.classList.remove('show');
    });
  }
});

    Your complete HTML, CSS and JS would become:

    document.querySelectorAll('.dropdown').forEach((dropdown) => {
  const button = dropdown.querySelector('a[data-toggle="dropdown"]');
  const menu = dropdown.querySelector('.dropdown-menu');

  button.addEventListener('click', (event) => {
    event.preventDefault();

    document.querySelectorAll('.dropdown-menu.show').forEach((openMenu) => {
      if (openMenu !== menu) {
        openMenu.classList.remove('show');
      }
    });

    const buttonWidth = button.offsetWidth;
    menu.style.width = `${buttonWidth}px`;

    // Toggle the visibility of the dropdown menu
    menu.classList.toggle('show');
  });
});

document.addEventListener('click', (event) => {
  if (!event.target.closest('.dropdown')) {
    document.querySelectorAll('.dropdown-menu.show').forEach((menu) => {
      menu.classList.remove('show');
    });
  }
});
     nav {
   width: 100px;  
 }
   

.nav-menu {
   background-color: orange;
 }
 
 .dropdown {
    position: relative;
  }
   
  
  a[data-toggle="dropdown"] {
    display: flex;
    align-items: center;
    background: transparent;
    color: blue;
    padding: 10px 15px;
    border-radius: 4px;
    transition: background 0.3s ease;
    white-space: nowrap;
  }
  
  a[data-toggle="dropdown"]:hover {
    color: black;
  }

.nav-menu {
    display: flex;
    flex-wrap: wrap; 
    gap: 10px;
    list-style-type: none;
    padding: 0;
    margin: 0;
    align-items: center;
    width: 100%;
    
}


  .dropdown-menu {
  list-style: none;
  padding: 10px 15px;
  margin: 0;
  position: absolute;
  top: 100%;
  left: 0;
  background: #ffffff;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.15);
  border-radius: 6px;
  overflow: hidden;
  transform: scaleY(0);
  transform-origin: top;
  opacity: 0;
  transition: transform 0.3s ease, opacity 0.3s ease;
  z-index: 1000;

  /* just need to add this - this will remove any preset width or min-width */
  width: auto;
  min-width: unset;
}
  
  
    
  .dropdown-menu.show {
    transform: scaleY(1);
    opacity: 1;
  }
  
  .dropdown-menu:before {
    /* content: ""; */
    display: block;
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    clip-path: inset(0 0 0 0);
  }
    <!-- UNCHANGED - NOTHING NEEDS TO BE CHANGED HERE IN HTML -->
<nav>
    <ul class="nav-menu">

        <li class="dropdown">
            <a href="#" data-toggle="dropdown">About</a>
            <ul class="dropdown-menu">
              <li><a href="/foo.html">Foo</a></li>
              <li><a href="/bar.html">Bar</a></li>
            </ul>
       </li>

    </ul>
</nav>