function _QueryString_find(key) {
   var value = null;
   for (var i=0;i<this.keys.length;i++) {
      if (this.keys[i]==key) {
	 value = this.values[i];
	 break;
      }
   }
   return value;
}

function _QueryString_parse() {
   var query = window.location.search.substring(1);
   var pairs = query.split("&");

   for (var i=0;i<pairs.length;i++) {
      var pos = pairs[i].indexOf('=');
      if (pos >= 0) {
	 var argname = pairs[i].substring(0,pos);
	 var value = pairs[i].substring(pos+1);
	 this.keys[this.keys.length] = argname;
	 this.values[this.values.length] = value;
      }
   }
}

function QueryString() {
   this.keys = new Array();
   this.values = new Array();
   this.parse = _QueryString_parse;
   this.find = _QueryString_find;
}

/* USAGE
   QueryString.keys = new Array();
   QueryString.values = new Array();
   QueryString_Parse();

   function saveSource() {
     document.survey.Source_Cell.value=QueryString('Source_Cell');
   }
*/