In IE6, when you specify javascript:void(0); in href and use onclick, you must write return false; at the end of onclick, otherwise it won’t work.

■ Code that doesn’t work in IE6

■ Code that works in IE6 (write return false; at the end of onclick)

Being troubled by IE6 again…

【Reference】

・javascript: void(0); のIEでの挙動 - 雑想空間

・javascript:void(0) のIE6での注意点/WEBサイト作成の注意点 »サイト構築日記

That’s all from the Gemba.