When an element's style.border is set to "0", the border-style and border-color attributes are set implicitly. Repeatedly calling style.border = "0" causes the implicitly border styles to be added to the element again, instead of updating the existing value.
For example, after setting border.style = "0" twice. The value of the style attribute is:
border-style: initial; border-color: initial; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial;
The border-style and border-color attributes are listed twice, and will be listed again every time the style.border value is set.
A test case is attached. This behavior is visible on Safari 4.0.5 and Chrome 5.0.342.9 beta on Mac OS 10.5 and 10.6
Created attachment 54891 [details]