Element.getBoundingClientRect()

The Element.getBoundingClientRect() method returns the size of an element and its position relative to the viewport.

Syntax

rectObject = object.getBoundingClientRect();

Value

The returned value is a DOMRect object which is the union of the rectangles returned by getClientRects() for the element, i.e., the CSS border-boxes associated with the element.

The returned value is a DOMRect object, which contains read-only left, top, right, bottom, x, y, width, height properties describing the border-box in pixels. Properties other than width and height are relative to the top-left of the viewport.

Empty border-boxes are completely ignored. If all the element's border-boxes are empty, then a rectangle is returned with a width and height of zero and where the top and left are the top-left of the border-box for the first CSS box (in content order) for the element.

The amount of scrolling that has been done of the viewport area (or any other scrollable element) is taken into account when computing the bounding rectangle. This means that the rectangle's boundary edges (top, left, bottom, and right) change their values every time the scrolling position changes (because their values are relative to the viewport and not absolute). If you need the bounding rectangle relative to the top-left corner of the document, just add the current scrolling position to the top and left properties (these can be obtained using window.scrollX and window.scrollY) to get a bounding rectangle which is independent from the current scrolling position.

Scripts requiring high cross-browser compatibility can use window.pageXOffset and window.pageYOffset instead of window.scrollX and window.scrollY. Scripts without access to these properties can use code like this:

// For scrollX
(((t = document.documentElement) || (t = document.body.parentNode))
  && typeof t.scrollLeft == 'number' ? t : document.body).scrollLeft
// For scrollY
(((t = document.documentElement) || (t = document.body.parentNode))
  && typeof t.scrollTop == 'number' ? t : document.body).scrollTop

Example

// rect is a DOMRect object with eight properties: left, top, right, bottom, x, y, width, height
var rect = obj.getBoundingClientRect();

Specifications

Notes

getBoundingClientRect() was first introduced in the MS IE DHTML object model.

The return value of getBoundingClientRect() is frozen.

Browser compatibility

[1] CSS spec for 'use' element referencing 'symbol' element requires default width and height for the <use> element set to 100%. Also spec for width and height 'svg' attributes requires 100% as default values. Google Chrome does not follow these requirements for <use>. Also Chrome does not take stroke-width into account. So getBoundingClientRect() may return different rectangles for Chrome and for Firefox.

[2] In IE8 and below, the DOMRect object returned by getBoundingClientRect() lacks height and width properties. Also, additional properties (including height and width) cannot be added onto these DOMRect objects.

[3] Gecko 1.9.1 adds width and height properties to the DOMRect object.

Starting in Gecko 12.0 (Firefox 12.0 / Thunderbird 12.0 / SeaMonkey 2.9), the effect of CSS transforms is considered when computing the element's bounding rectangle.

See also

• MSDN: getBoundingClientRect Method
• getClientRects()