Why Doesn't My Div Show Up On Top Despite a High z-index Value?

z-index Property in CSS

In HTML, you may encounter issues with displaying elements overlapped by other elements, such as a div positioned behind another element despite having a high z-index value. To address this, it's important to understand the nature and limitations of the z-index property in CSS.

No Minimum or Maximum Value in CSS Standard

According to the CSS standards, the z-index property has no inherent minimum or maximum value. However, this is not true in practice.

Browser Limitations

Most web browsers impose limitations on the range of valid z-index values. Typically, these browsers use signed 32-bit values, which range from -2,147,483,648 to 2,147,483,647. Values outside this range may not be recognized.

Example Issue

In the given example, the div with the class "divClass" may not be displaying above the other elements because the browser is limiting the z-index value to 32-bit integers. The value of 1000 is within the valid range, but other elements on the page may have higher z-index values, causing them to overlap the div.

Solution

To resolve such issues, ensure that the z-index value you are using is higher than any other element that could potentially overlap your div. If the problem persists, check the browser's developer tools to identify any elements with higher z-index values. You can then adjust the z-index value of the div accordingly to ensure it displays on top.

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