function get_url_param(targetvar) 
{ 
	var fullurl=window.location.search; var param=(fullurl.slice(1)); var pairs = param.split("&") 
	for(var i = 0; i < pairs.length; i++) 
		{ var pos = pairs[i].indexOf('='); if (pos == -1) continue; var argname = pairs[i].substring(0,pos); var value = pairs[i].substring(pos+1); if (argname == targetvar) { var targetvalue = value; {break} } 		} 
	return targetvalue;
	//	document.write(targetvar + ': <input type="text" name="' + targetvar + '" value="' + targetvalue + '">' );
} 
function pass_promo_code(fieldname,defaultvalue){
	promocode = get_url_param(fieldname);
	if (promocode == undefined) promocode = defaultvalue;
	document.write('<input type="hidden" name="' + fieldname + '" value="' + promocode + '">' );
}