CSS Reference Property

left

The left property is an offset property that is used to specify the left offset of a positioned element with respect to its positioning context.

It is one of four available offset properties that also include right, top, and bottom.

Offset properties are used to specify the exact position of a positioned element and have no effect on non-positioned (static) elements. In order to use this property, the element should have a position value other than the default static.

The left property specifies how far an absolutely positioned element’s left margin edge is offset relative to the left edge of the element’s positioning context, which is usually its containing block. For relatively positioned elements, the offset is with respect to the left edge of the element itself (i.e., the element is given a position in the normal flow, then offset from that position according to the offset properties). For fixed and sticky elements the positioning context is the viewport.

You should read the position property entry for details on how to choose a position for an element to use the offset properties on it.

Official Syntax

  • Syntax:

    left: <length> | <percentage> | auto
  • Initial: auto
  • Applies To: positioned elements
  • Animatable: yes, as a length, percentage or calc();

Values

<length>

The left offset is specified as a fixed length. See the <length> entry for a list of possible length values and units.

Negative values are allowed. A positive value will offset the element to the right from the left edge of its positioning context, while a negative value will offset to the left with respect to the left edge of the context.

<percentage>

The left offset is specified as a percentage of its containing block’s height. See the <length> entry for a list of possible length values and units.

Negative values are allowed. A positive value will offset the element to the right from the left edge of its positioning context, while a negative value will offset to the left with respect to the left edge of the context.

auto
When left is set to auto then:

  • If the element is relatively positioned, it will be positioned (horizontally) according to the value of the right property, and if the right property is also set to auto, the element is not offset horizontally at all. (It could still be offset vertically using one of the vertical offset properties top and bottom.)
  • If the element is absolutely positioned, it will be positioned (horizontally) according to the value of the right property, and if its width is width: auto, it will get its width based on its content—it usually expands to fill the entire available width inside its containing block.

Notes

The left offset property also accepts a value of inherit, which allows the element to inherit its left offset from its parent. The element’s parent may not be its positioning context.

Examples

The following example offsets an absolutely positioned element by 30px the the right of the left edge of its containing block (which in this case is its positioning context).

.container {
    position: relative; /* establishes a positioning context for its absolutely positioned descendants and for itself */
}

.absolutely-positioned {
    position: absolute;
    left: 30px;
}
                

Browser Support

The left property is supported in all major browsers: Chrome, Firefox, Safari, Opera, Internet Explorer, and on Android and iOS.

Written by

Last updated February 4, 2015 at 3:33 pm by Mary Lou

Do you have a suggestion, question or want to contribute? Submit an issue.