css45 CSS Math Functions

emanlee發表於2024-06-01
CSSFunction

https://www.w3schools.com/css/css_math_functions.asp

The CSS math functions allow mathematical expressions to be used as property values. Here, we will explain the calc(), max() and min() functions.

The calc() Function

The calc() function performs a calculation to be used as the property value.

CSS Syntax

calc(expression)
ValueDescription
expression Required. A mathematical expression. The result will be used as the value.
The following operators can be used: + - * /

Let us look at an example:

Example

Use calc() to calculate the width of a <div> element:

#div1 {
position: absolute;
left: 50px;
width: calc(100% - 100px);
border: 1px solid black;
background-color: yellow;
padding: 5px;
} 
<!DOCTYPE html>
<html>
<head>
<style>
#div1 {
  position: absolute;
  left: 50px;
  width: calc(100% - 100px);
  border: 1px solid black;
  background-color: yellow;
  padding: 5px;
}
</style>
</head>
<body>

<h1>The calc() Function</h1>

<p>Create a div that stretches across the window, with a 50px gap between both sides of the div and the edges of the window:</p>

<div id="div1">Some text...</div>

</body>
</html>


The max() Function

The max() function uses the largest value, from a comma-separated list of values, as the property value.

CSS Syntax

max(value1, value2, ...)
ValueDescription
value1, value2, ... Required. A list of comma-separated values - where the largest value is chosen

Let us look at an example:

Example

Use max() to set the width of #div1 to whichever value is largest, 50% or 300px:

#div1 {
background-color: yellow;
height: 100px;
width: max(50%, 300px);
} 
<!DOCTYPE html>
<html>
<head>
<style>
#div1 {
  background-color: yellow;
  height: 100px;
  width: max(50%, 300px);
}
</style>
</head>
<body>

<h1>The max() Function</h1>

<p>Use max() to set the width of #div1 to whichever value is largest, 50% or 300px:</p>

<div id="div1">Some text...</div>

<p>Resize the browser window to see the effect.</p>

</body>
</html>

The min() Function

The min() function uses the smallest value, from a comma-separated list of values, as the property value.

CSS Syntax

min(value1, value2, ...)
ValueDescription
value1, value2, ... Required. A list of comma-separated values - where the smallest value is chosen

Let us look at an example:

Example

Use min() to set the width of #div1 to whichever value is smallest, 50% or 300px:

#div1 {
background-color: yellow;
height: 100px;
width: min(50%, 300px);
} 

<!DOCTYPE html>
<html>
<head>
<style>
#div1 {
  background-color: yellow;
  height: 100px;
  width: min(50%, 300px);
}
</style>
</head>
<body>

<h1>The min() Function</h1>

<p>Use min() to set the width of #div1 to whichever value is smallest, 50% or 300px:</p>

<div id="div1">Some text...</div>

<p>Resize the browser window to see the effect.</p>

</body>
</html>

All CSS Math Functions

FunctionDescription
calc() Allows you to perform calculations to determine CSS property values
max() Uses the largest value, from a comma-separated list of values, as the property value
min() Uses the smallest value, from a comma-separated list of values, as the property value

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