function GetParam(name)
{
 var start=location.search.indexOf("?"+name+"=" );
 if (start<0) start=location.search.indexOf("&"+name+"=" );
 if (start<0) return '';
 start += name.length+2;
 var end=location.search.indexOf("&",start)-1;
 if (end<0) end=location.search.length;
 var result='';
 for(var i=start;i<=end;i++) {
  var c=location.search.charAt(i);
  result=result+(c=='+'?' ':c);
 }
 return unescape(result);
}
...
nom_dans_url=GetParam("type_recherche" );