public String getWebVar(String s, String webvar){
	// given a query_string and a webvar, return the value
	int posStart, posEnd;
	String ret;
	ret = "";
	posStart = s.indexOf( webvar + "=" );

	if( posStart >= 0 ){
		String s2 = "";
		posStart += webvar.length() + 1;
		s2 = s.substring( posStart, s.length());
		posEnd = s2.indexOf( "&");

		if ( posEnd >= 0 ){
			// do nothing
		}else{
			posEnd = s2.length();
		}
		posEnd = posStart + posEnd; 
		ret = s.substring( posStart, posEnd );
	}
	return ret;
}

String tmpurl = "/db.nsf/agent?openagent&szip=10577&smethod=1&sweight=35";

String tmpvalue = getWebVar(tmpurl, "sweight");