How to Prevent Bootstrap Scrollable Menu from Expanding its Container?

Scrollable Menu with Bootstrap: Addressing Container Expansion Issues

Introduction

Creating a scrollable menu in Bootstrap is a common requirement. However, in some implementations, it has been observed that the scrollable menu expands its container, resulting in undesired behavior. This article seeks to provide a solution to this issue.

Understanding the Issue with Container Expansion

In the method described in the question, the use of multiple nested dropdown-menu elements can lead to the outer container expanding when the scrollable menu is populated with a large number of items. This expansion occurs because the outer container's width adjusts to accommodate the increasing width of the nested dropdown menus.

解决方案

To address this issue, a separate CSS class can be applied to the scrollable menu, such as scroll-menu. Within this class, the以下 CSS properties should be specified:

.scroll-menu {
    height: auto;
    max-height: [desired height];
    overflow-y: auto;
}

Updated HTML:

The following HTML snippet demonstrates how to apply the scroll-menu class to a scrollable menu:

<ul class="dropdown-menu scroll-menu">
    <!-- Scrollable menu items here -->
</ul>

Alternative Approaches

Additionally, the following alternative approaches can be considered:

• Bootstrap 5: Use max-height to make the dropdown scrollable:

.dropdown-menu {
    max-height: 280px;
    overflow-y: auto;
}

• Bootstrap 4: Set max-height on the specific menu class:

.my-scrollable-menu {
    max-height: 280px;
    overflow-y: auto;
}

• Horizontal Menu: Consider using a horizontal menu that natively provides scrolling functionality, eliminating the need for custom CSS.

Conclusion

By applying the suggested CSS class and properties to the scrollable menu, the container expansion issue can be resolved. Alternatively, the suggested alternative approaches offer additional options for creating scrollable menus that address this problem.

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