How to set drop-down box in css

CSS is a programming language for style and layout, commonly used in the design and development of Web sites and applications. Among them, the drop-down box is a common UI element, usually used to select options in a list. This article will introduce how to use CSS to set up a drop-down box.

HTML Basics

Before introducing the CSS setting of the drop-down box, we need to first understand the drop-down box mark in HTML. HTML provides a select tag and multiple option tags for the drop-down box to specify the options in the drop-down box. Here is a basic drop-down box example:

 选项1 选项2 选项3 

With the above code, we can create a drop-down box containing three options. Next, we'll beautify and customize it using CSS.

Set the style of the drop-down box

It is very simple to set the style of the drop-down box using CSS. You only need to use the select selector to select the drop-down box and set its properties. The following are some commonly used drop-down box style settings:

Set the drop-down box width and height

select { width: 200px; /* 设置宽度 */ height: 30px; /* 设置高度 */ }

Set the drop-down box border and background color

select { border: 1px solid #ccc; /* 设置边框 */ background-color: #f7f7f7; /* 设置背景色 */ }

Set the drop-down box font and color

select { font-size: 16px; /* 设置字体大小 */ color: #333; /* 设置字体颜色 */ }

Set the drop-down box arrow style

select { appearance: none; /* 去掉默认箭头 */ background-image: url('arrow.svg'); /* 设置自定义箭头 */ background-position: center right; /* 设置箭头位置 */ background-repeat: no-repeat; /* 禁止重复 */ padding-right: 30px; /* 设置右内边距 */ }

Through the above code, we can make the default style drop-down box more beautiful and personalized, so that it can better adapt to our design needs.

Customized drop-down box style

In addition to using CSS to set the basic style of the drop-down box, we can also create specific drop-down box effects through custom styles and HTML code. Here are some examples:

Custom drop-down box simulates a select box

  选项1 选项2 选项3  
 

.select-box { position: relative; display: inline-block; } select { width: 100%; height: 100%; opacity: 0; position: absolute; top: 0; left: 0; z-index: 1; } .select-arrow { position: absolute; top: 50%; right: 5px; transform: translateY(-50%); width: 8px; height: 8px; background-color: #666; clip-path: polygon(50% 0%, 0% 100%, 100% 100%); }

With the above code, we can create a drop-down box similar to a select box, making it work better with other forms elements to match.

Custom drop-down box simulates scroll bar

  选项1 选项2 选项3 选项4 选项5 选项6 选项7 选项8 选项9 选项10 选项11 选项12 选项13 选项14 选项15 选项16 选项17 选项18 选项19 选项20  
 
 
 

.select-box { position: relative; display: inline-block; width: 200px; height: 40px; } select { width: 100%; height: 100%; opacity: 0; position: absolute; top: 0; left: 0; z-index: 1; } .select-scrollbar { position: absolute; right: 0; top: 0; width: 8px; height: 100%; background-color: #f7f7f7; z-index: 2; overflow-y: scroll; } .select-scrollbar-thumb { position: relative; width: 100%; height: 50%; background-color: #ccc; border-radius: 4px; z-index: 3; }

With the above code, we can create a drop-down box that is similar to a scroll bar so that it can better adapt to a long list of options.

Summary

This article introduces how to use CSS to set the basic style and custom style of the drop-down box. Through these technologies, we can create different styles of drop-down boxes to meet different design needs. When using CSS to style drop-down boxes, we need to pay attention to issues such as compatibility and performance to ensure page stability and user experience.

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