extra Postback

[CreativeMind]

hi all,
i have not set autopostback=true for radiobutton (a dropdown enables
or disables on its check or uncheck , moreover i haven't set
autopostback =true for this dropdown). i make radio button checked or
unchecked in javascript and code-behind as well.

but sometimes i find autopostback code on the rendered html against
that radiobutton.. what's problem ?

<input id="_ctl0_ContentPlaceHolder2_rdoStatus" type="radio"
name="_ctl0:ContentPlaceHolder2:GrpDate" value="rdoStatus"
onclick="javascript:changeOption(_ctl0_ContentPlaceHolder2_rdoStatus);setTimeout('__doPostBack(\'_ctl0$ContentPlaceHolder2$rdoStatus
\',\'\')', 0)" language="javascript" /><label
for="_ctl0_ContentPlaceHolder2_rdoStatus">

thanx.