# rotateX()

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The `rotateX()` CSS function defines a transformation that rotates an element around the abscissa (horizontal axis) without deforming it. Its result is a `<transform-function>` data type.

The axis of rotation passes through an origin, defined by the `transform-origin` CSS property.

Note: `rotateX(a)` is equivalent to `rotate3d(1, 0, 0, a)`.

Note: Unlike rotations in the 2D plane, the composition of 3D rotations is usually not commutative. In other words, the order in which the rotations are applied impacts the result.

## Syntax

The amount of rotation created by `rotateX()` is specified by an `<angle>`. If positive, the movement will be clockwise; if negative, it will be counter-clockwise.

```rotateX(a)
```

### Values

`a`
Is an `<angle>` representing the angle of the rotation. A positive angle denotes a clockwise rotation, a negative angle a counter-clockwise one.
Cartesian coordinates on ℝ2 Homogeneous coordinates on ℝℙ2 Cartesian coordinates on ℝ3 Homogeneous coordinates on ℝℙ3
This transformation applies to the 3D space and can't be represented on the plane. $\left(\begin{array}{ccc}1& 0& 0\\ 0& cos\left(a\right)& -sin\left(a\right)\\ 0& sin\left(a\right)& cos\left(a\right)\end{array}\right)$ $\left(\begin{array}{cccc}1& 0& 0& 0\\ 0& cos\left(a\right)& -sin\left(a\right)& 0\\ 0& sin\left(a\right)& cos\left(a\right)& 0\\ 0& 0& 0& 1\end{array}\right)$

## Examples

### HTML

```<div>Normal</div>
<div class="rotated">Rotated</div>```

### CSS

```div {
width: 80px;
height: 80px;
background-color: skyblue;
}

.rotated {
transform: rotateX(45deg);
background-color: pink;
}
```

## Specifications

Specification Status Comment
CSS Transforms Level 2
The definition of 'rotateX()' in that specification.
Editor's Draft Initial definition

## Browser compatibility

Please see the `<transform-function>` data type for compatibility info.