VB3.8.1 - BB code (Spoiler) problem with Firefox /need help....

[honggie]

i use custom bbcode for spoiler button
the button show on the post but nothing happen when click the button

only forefox
opera and ie work fine

before upgrade from 3.6.4 no any problem with spoiler bbcode

how to fix this????
(my vb version 3.8.1)


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here the code in replacement box

<div id="spoiler"><div><input type="button" value="Show Spoiler!" style="width:100px;font-size:11px;margin:10px;padding:0px;" onclick="if (this.parentNode.parentNode.getElementsByTagName('div')['show'].style.display != '') { this.parentNode.parentNode.getElementsByTagName('div')['show'].style.display = ''; this.parentNode.parentNode.getElementsByTagName('div')['hide'].style.display = 'none'; this.innerText = ''; this.value = 'Hide Spoiler!'; } else { this.parentNode.parentNode.getElementsByTagName('div')['show'].style.display = 'none'; this.parentNode.parentNode.getElementsByTagName('div')['hide'].style.display = ''; this.innerText = ''; this.value = 'Show Spoiler!'; }" />
<div id="show" style="background-color:#e0eeff; display: none; background-color:transparent; background-repeat:repeat; margin-left: 10px;margin-top: 0px; border-style:solid;border-width:1px; padding: 5px; width:90%">
{param}</div>
<div id="hide"></div></div></div>