Search Control causes ASPX page to Postback twice

<div id="WLSearchBoxDiv">
<table cellpadding="0" cellspacing="0"><tr id="WLSearchBoxPlaceholder">
<td id="WLSearchBoxPrefixTD"><asp:Label ID="WLSearchBoxPrefix" runat="server" /></td>
<td style="width: 100%; border:solid 2px #4B7B9F;border-right-style: none;"><input id="WLSearchBoxInput" type="text" value="&#x4c;&#x6f;&#x61;&#x64;&#x69;&#x6e;&#x67;&#x2e;&#x2e;&#x2e;" disabled="disabled" style="padding:0;background-image: url(http://search.live.com/s/siteowner/searchbox_background.png);background-position: right;background-repeat: no-repeat;height: 16px; width: 100%; border:none 0 Transparent" /></td><td style="border:solid 2px #4B7B9F;"><input id="WLSearchBoxButton" type="image" src="http://search.live.com/s/siteowner/searchbutton_normal.png" align="absBottom" style="padding:0;border-style: none" /></td></tr></table>
<script type="text/javascript" charset="utf-8">
var WLSearchBoxConfiguration=
{
"global":{
"serverDNS":"search.live.com",
"market":"en-US"
},
"appearance":{
"autoHideTopControl":false,
"width":800,
"height":550,
"theme":"Blue"
},
"scopes":[
{
"type":"web",
"caption":"&#x54;&#x68;&#x69;&#x73;&#x20;&#x73;&#x69;&#x74;&#x65;",
"searchParam":"site:www.josephguadagno.net"
}
,
{
"type":"web",
"caption":"&#x53;&#x65;&#x61;&#x72;&#x63;&#x68;&#x20;&#x43;&#x6f;&#x64;&#x65;&#x20;&#x53;&#x69;&#x74;&#x65;&#x73;",
"searchParam":"macro:guadagno.Code_Search"
}
,
{
"type":"web",
"caption":"&#x57;&#x65;&#x62;",
"searchParam":""
}
]
}
</script>
<script type="text/javascript" charset="utf-8" src="http://search.live.com/bootstrap.js?market=en-US&ServId=SearchBox&ServId=SearchBoxWeb&Callback=WLSearchBoxScriptReady"></script>
</div>

/* Windows Live Search Box - START */
#WLSearchBoxDiv
{
display: block;
text-align: right;
padding-left: 5px;
padding-right: 5px;

}
#WLSearchBoxPlaceholder
{
background-color:Aqua;
text-align: right;
width: 100%;
}