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#3742 closed bug (fixed)

Opened December 23, 2008 08:11PM UTC

Closed January 20, 2009 02:55AM UTC

Last modified March 14, 2012 10:44PM UTC

offset() uses parseInt which rounds down decimal numbers

Reported by: ktrott Owned by: brandon
Priority: major Milestone: 1.3
Component: offset Version: 1.2.6
Keywords: Cc: ktrott
Blocked by: Blocking:

In Firefox 3, the value of getBoundingClientRect for top or bottom may be a decimal number, e.g. 602.75 or 602.25.

Firefox appears to render at the actual position of 603 for 602.75. Since jQuery offset method uses parseInt it ends up returning 602. If you are doing exact positioning you end up being off by 1 pixel.

One could argue that jQuery shouldn't make assumptions about how the browser implements the decimal numbers and instead return decimal numbers rather than ints, e.g. return 602.75 rather than 602 or 603. Then when one positions an element at 602.75, the browser would internally handle it.

Here's a workaround we wrote that addressed our use case by patching up the jQuery offset return values:

var offset = $elem.offset(),

elem = $elem.get(0);

if (elem.getBoundingClientRect) {

var rect = elem.getBoundingClientRect();

if (!isNaN(parseInt( { += ( - parseInt(;


if (!isNaN(parseInt(rect.left))) {

offset.left += (rect.left - parseInt(rect.left));



return offset;

Attachments (0)
Change History (2)

Changed December 25, 2008 08:53PM UTC by flesler comment:1

cc: → ktrott
component: unfilledoffset
owner: fleslerbrandon

Changed January 20, 2009 02:55AM UTC by brandon comment:2

resolution: → fixed
status: newclosed

This is actually fixed in jQuery 1.3