Slide animation broken on jQuery 1.10.0 ?

[[email protected]…]

I just upgraded to jQuery 1.10.0 from 1.9.1 and found that this animation breaks on multiple browsers--it slides very fast and twitches in a strange way:

$(document).on('click','#my-btn',function(){

$('#my-div').show('slide', 250);

});

I'm using jQuery UI 1.10.3 in both the failing jQuery 1.10.0 and successful jQuery 1.9.1 cases.

Oddly enough, the hide('slide',250) works as normal.

[niphor]

Yes,the same issue here

a simple demo on jsFiddle change jquery version from 1.10 to 1.9.1 to see the difference... ​http://jsfiddle.net/niphor/53Dxj/

2.0.1 also have the same issue.

[[email protected]…]

Yep, that's exactly the behavior I see.

[niphor]

I trace the source code of 1.10.0 the problem is here: assume user's code is:

$('#slide3').animate({ left: '+=200' }, 500);
or
$('#slide3').animate({ left: '+=200px' }, 500);

in the 'tweeners[*] ' at line 8830 of the source code,at this point:

parts should be ['+=200','+','100',] or ['+=200','+','100','px'] then:

unit = parts && parts[ 3 ] || ( jQuery.cssNumber[ prop ] ? "" : "px" )

jQuery.cssNumber[ prop ] eqs jQuery.cssNumber[ 'left' ], the value === null

so: unit ==="px"

start = ( jQuery.cssNumber[ prop ] || unit !== "px" && +target ) &&
                                        rfxnum.exec( jQuery.css( tween.elem, prop ) )

then unit!=="px" always ===false

so: start=false

//line 8870
tween.end = parts[ 1 ] ?start + ( parts[ 1 ] + 1 ) * parts[ 2 ] : +parts[ 2 ];

because start=false ,start+(parts[1]+1)*parts[2] = false+ +1*200= 200

so:tween.end=200

but it should be 0;

[creage]

I double that, and want to point that is same bug exists in 2.0.1 as well. Really stops from upgrading...

[scottgonzalez]

Duplicate of #13939.