Can You Position Elements Absolutely Without Explicit Top, Left, Bottom, Right Values?

Positioning Elements Absolutely Without Explicit Top/Left/Bottom/Right Values: A Dive into the Standard

In the realm of web development, absolute positioning allows elements to be placed independently of their normal flow in the document. However, a common question arises when attempting to achieve this without explicitly setting the top/left/bottom/right properties.

Default Behavior for Auto Values

According to the CSS2 specification, the default behavior for auto values in the top/bottom, left/right properties is to assign them the same values as they would have in the static position. This means that an element with position: absolute and all four auto values will behave as if it were statically positioned.

Case #1: Logo Above Photo in WordPress Header

In the first case, positioning the logo absolutely above the photo without explicit top/left/bottom/right values is possible because the logo element is the first child of its parent container (header). As the CSS standard states, an absolutely positioned first child with margins (or padding) will be shifted in relation to its parent's top left corner.

Case #2: Horizontal Multi-Level Menu

In the second case, the horizontal multi-level menu can be laid out using display: table-*, but table cells do not support relative positioning. However, by using position: absolute on the menu items and leaving the top/bottom, left/right properties as auto, the default behavior will ensure that these items are positioned according to their static position values, effectively emulating relative positioning within the table cell context.

Browser Compatibility

While this technique adheres to the CSS2 specification and should work in theory, it is important to note that browser support for absolute positioning without explicit top/left/bottom/right values may vary. Some older browsers, such as Firefox 0.8 and IE6-7, may exhibit unexpected behavior. Nevertheless, it remains a valid approach that can provide flexibility in certain situations.

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