Why Does the Top Margin of an Element After a Float Sometimes Disappear?

The Ignored Top Margin of HTML Elements After Floats

In web development, it's common to use floats to position elements alongside each other. However, when a floated element is present, the top margin of a subsequent element can be ignored in certain browsers.

This behavior stems from the fact that floats are removed from the normal flow of the document, causing succeeding block-level elements to flow as if the float didn't exist. This can result in the second element being visually adjacent to the first, despite having a specified top margin.

Consider the following example:

<div>

In this scenario, the second div is expected to be separated from the first by a 90px top margin. However, in Firefox or IE8, the second div will appear to be touching the first.

Solution: Wrapping with Internal White Space

To rectify this issue, a common solution is to wrap the second div within another element. This wrapper element will act as a buffer between the second div and the floated element. Additionally, the wrapper's white space should be specified using padding rather than margin. This helps ensure that the padding is not affected by external elements.

Here's a modified version of the example:

<div>

With this modification, the wrapper element establishes a 90px padding at the top, effectively separating the second div from the floated element as intended.

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