function list_dados(valor ) {
      http.open("GET", "php/result.php?id=" + valor, true);
      http.onreadystatechange = handleHttpResponse;
      http.send(null);    }
	  
      function handleHttpResponse()    {	  
	  document.forms[1].cidade.disabled = false;
      campo_select = document.forms[1].cidade;
      if (http.readyState == 4) {
      campo_select.options.length = 0;
      results = http.responseText.split(",");
      for( i = 0; i < results.length; i++ )  {
      string = results[i].split( "|" );
      campo_select.options[i] = new Option( string[0], string[1] );
      }      }      }
      function getHTTPObject() {
      var req;
      try {
      if (window.XMLHttpRequest) {
      req = new XMLHttpRequest();
      if (req.readyState == null) {
      req.readyState = 1;
      req.addEventListener("load", function () {
      req.readyState = 4;
      if (typeof req.onReadyStateChange == "function")
      req.onReadyStateChange();
      }, false);
      }
      return req;
      }
      if (window.ActiveXObject) {
      var prefixes = ["MSXML2", "Microsoft", "MSXML", "MSXML3"];
      for (var i = 0; i < prefixes.length; i++) {
      try {
      req = new ActiveXObject(prefixes[i] + ".XmlHttp");
      return req;
      } catch (ex) {};
      }      }      } 
	  catch (ex) {}
      alert("XmlHttp Objects not supported by client browser");
      }
      var http = getHTTPObject();
      // Logo após fazer a verificação, é chamada a função e passada
      // o valor à variável global http.