<filter-function>

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2016.

The <filter-function> CSS data type represents a graphical effect that can change the appearance of an input image. It is used in the filter and backdrop-filter properties.

Syntax

The <filter-function> data type is specified using one of the filter functions listed below. Each function requires an argument which, if invalid, results in no filter being applied.

blur(): Blurs the image.
brightness(): Makes the image brighter or darker.
contrast(): Increases or decreases the image's contrast.
drop-shadow(): Applies a drop shadow behind the image.
grayscale(): Converts the image to grayscale.
hue-rotate(): Changes the overall hue of the image.
invert(): Inverts the colors of the image.
opacity(): Makes the image transparent.
saturate(): Super-saturates or desaturates the input image.
sepia(): Converts the image to sepia.

Formal syntax

<filter-function> = 
  <blur()>         |
  <brightness()>   |
  <contrast()>     |
  <drop-shadow()>  |
  <grayscale()>    |
  <hue-rotate()>   |
  <invert()>       |
  <opacity()>      |
  <sepia()>        |
  <saturate()>     

<blur()> = 
  blur( <length>? )  

<brightness()> = 
  brightness( [ <number> | <percentage> ]? )  

<contrast()> = 
  contrast( [ <number> | <percentage> ]? )  

<drop-shadow()> = 
  drop-shadow( [ <color>? && <length>{2,3} ] )  

<grayscale()> = 
  grayscale( [ <number> | <percentage> ]? )  

<hue-rotate()> = 
  hue-rotate( [ <angle> | <zero> ]? )  

<invert()> = 
  invert( [ <number> | <percentage> ]? )  

<opacity()> = 
  opacity( [ <number> | <percentage> ]? )  

<sepia()> = 
  sepia( [ <number> | <percentage> ]? )  

<saturate()> = 
  saturate( [ <number> | <percentage> ]? )

This example provides a simple graphic, along with a select menu to allow you to choose between the different types of filter function, and a slider to allow you to vary the values used inside the filter function. Updating the controls updates the filter effect in real time, allowing you to investigate the effects of different filters.

css

div {
  width: 100%;
  height: 512px;
  background: url(fx-nightly-512.png);
  background-repeat: no-repeat;
  background-position: center center;
  filter: <filter-function>(<value>);
}

Where the <filter-function> is the filter you select from the drop down and the <value> is the values you set with the slider:

html

<div></div>
<ul>
  <li>
    <label for="filter-select">Choose a filter function:</label>
    <select id="filter-select">
      <option selected>blur</option>
      <option>brightness</option>
      <option>contrast</option>
      <option>drop-shadow</option>
      <option>grayscale</option>
      <option>hue-rotate</option>
      <option>invert</option>
      <option>opacity</option>
      <option>saturate</option>
      <option>sepia</option>
    </select>
  </li>
  <li><input type="range" /><output></output></li>
  <li>
    <p>Current value: <code></code></p>
  </li>
</ul>

css

div {
  width: 100%;
  height: 512px;
  background-image: url(https://mdn.github.io/shared-assets/images/examples/fx-nightly-512.png);
  background-repeat: no-repeat;
  background-position: center center;
}

li {
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}

input {
  width: 60%;
}

output {
  width: 5%;
  text-align: center;
}

select {
  width: 40%;
  margin-left: 2px;
}

const selectElem = document.querySelector("select");
const divElem = document.querySelector("div");
const slider = document.querySelector("input");
const output = document.querySelector("output");
const curValue = document.querySelector("p code");

selectElem.addEventListener("change", () => {
  setSlider(selectElem.value);
  setDiv(selectElem.value);
});

slider.addEventListener("input", () => {
  setDiv(selectElem.value);
});

function setSlider(filter) {
  switch (filter) {
    case "blur":
      slider.value = 0;
      slider.min = 0;
      slider.max = 30;
      slider.step = 1;
      slider.setAttribute("data-unit", "px");
      break;
    case "brightness":
    case "contrast":
    case "saturate":
      slider.value = 1;
      slider.min = 0;
      slider.max = 4;
      slider.step = 0.05;
      slider.setAttribute("data-unit", "");
      break;
    case "drop-shadow":
      slider.value = 0;
      slider.min = -20;
      slider.max = 40;
      slider.step = 1;
      slider.setAttribute("data-unit", "px");
      break;
    case "opacity":
      slider.value = 1;
      slider.min = 0;
      slider.max = 1;
      slider.step = 0.01;
      slider.setAttribute("data-unit", "");
      break;
    case "grayscale":
    case "invert":
    case "sepia":
      slider.value = 0;
      slider.min = 0;
      slider.max = 1;
      slider.step = 0.01;
      slider.setAttribute("data-unit", "");
      break;
    case "hue-rotate":
      slider.value = 0;
      slider.min = 0;
      slider.max = 360;
      slider.step = 1;
      slider.setAttribute("data-unit", "deg");
      break;
    default:
      console.error("Unknown filter set");
  }
}

function setDiv(filter) {
  const unit = slider.getAttribute("data-unit");
  const offset = `${Math.round(slider.value)}${unit}`;
  const radius = `${Math.round(Math.abs(slider.value / 2))}${unit}`;
  divElem.style.filter =
    filter === "drop-shadow"
      ? `${selectElem.value}(${offset} ${offset} ${radius})`
      : `${selectElem.value}(${slider.value}${unit})`;

  updateOutput();
  updateCurValue();
}

function updateOutput() {
  output.textContent = slider.value;
}

function updateCurValue() {
  curValue.textContent = `filter: ${divElem.style.filter}`;
}

setSlider(selectElem.value);
setDiv(selectElem.value);

Specifications

Specification
Filter Effects Module Level 1 # typedef-filter-function

Browser compatibility

BCD tables only load in the browser