QueryStringinJavascript

///page.querystring[]
<script language=javascript>
function querystring(fieldname)
{

var urlstring = document.location.search;
if(urlstring != null)
{
var typequ = fieldname+"=";
var urlend = urlstring.indexof(typequ);
if(urlend != -1)
{
var paramsurl = urlstring.substring(urlend+typequ.length);
var isend = paramsurl.indexof('&');
if(isend != -1)
{
return paramsurl.substring(0, isend);
}
else
{
return paramsurl;
}
}
else
return null;
}
else
return null;
}
</script>

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