Why do Bootstrap Dropdowns appear behind other elements in IE7?

Bootstrap Dropdowns appearing behind other elements on IE7

Bootstrap 2.3.1 allows for the creation of dropdown menus using the 'dropdown-menu' class. However, users have encountered an issue where these menus appear behind other elements on IE7, despite setting the z-index CSS property.

Understanding the Issue: Stacking Context

To resolve this issue, one must understand the concept of stacking context. A stacking context is a three-dimensional space in which elements are stacked in the order they appear in the HTML code. The dropdown menu is appearing behind other elements because it is in a different stacking context than the overlays it is meant to hover over.

Fixing the Issue: Establishing a Stacking Context

To establish a stacking context for the dropdown menu, a z-index and position must be set on a parent element. In this case, the header-top div is an appropriate choice. Here's the CSS modification:

.header-top {
  z-index: 100;
  position: relative;
}

By setting the z-index to a higher value than other elements and assigning a position, the header-top div creates a new stacking context for the dropdown menu. This ensures that the menu appears above all other elements.

The above is the detailed content of Why do Bootstrap Dropdowns appear behind other elements in IE7?. For more information, please follow other related articles on the PHP Chinese website!