z-index is a CSS property that controls the order in which elements overlap on the page, similar to the order in which paper is stacked. Here's how it works: Every element has a default z-index value of 0. Elements with higher z-index values will overwrite elements with lower z-index values. z-index can be used to create floating elements, control the order of overlapping elements, and create three-dimensional effects. When using, you need to consider things such as avoiding overuse, using negative values, and paying attention to browser compatibility.
What is z-index?
z-index is a property in CSS (Cascading Style Sheets) used to control the order in which elements overlap on the page. It specifies the position of an element relative to other elements on the page, similar to the order in which paper is stacked.
How z-index works
Every HTML element has a default z-index value of 0. Elements with higher z-index values will overwrite elements with lower z-index values. For example:
<code class="css">#element1 { z-index: 10; } #element2 { z-index: 20; }</code>
In this case, #element2 will overwrite #element1 because it has a higher z-index value.
Uses of z-index
z-index is widely used in web design:
Notes on z-index
When using z-index, you need to consider the following:
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