Calling web service using XMLHttpRequest, CORS issue

Question

I'm disperate looking for a solution to cors issue. I have the following script in my html page

  var webserUrl = "http://www.webservicex.com/globalweather.asmx";
  var soapRequest =
  '<soapenv:Envelope  xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:web="http://www.webserviceX.NET"> '+
  '   <soapenv:Header/> '+
  '   <soapenv:Body> '+
  '      <web:GetCitiesByCountry> '+
  '         <!--Optional:--> '+
  '         <web:CountryName>SPAIN</web:CountryName> '+
  '      </web:GetCitiesByCountry> '+
  '   </soapenv:Body> '+
  '</soapenv:Envelope> ';

  var req = new XMLHttpRequest();
  req.open("POST", webserUrl);

  req.setRequestHeader("Content-Type","text/xml");
  req.setRequestHeader("Access-Control-Allow-Origin","*");
  req.send(soapRequest);
  req.addEventListener("readystatechange",function()
  { 
      console.log(req);
      alert(req.status);
      if (req.readyState === 4 )
      {
          alert(req.statusText);    
      }
      else {
          alert(req.readyState);
      }

  },false);

This is a free public web service, when I execute this on the browser (chrome) I obtain (looking for errors F12)

Failed to load resource: the server responded with a status of 404 (Not Found) jbondNi:1 Failed to load http://www.webservicex.com/globalweather.asmx: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://127.0.0.1:51131' is therefore not allowed access.

Please help how to solve this issue. Thank you