how to find if WWW Post Request is succesful?

How do I know if my post request has been received by the server or if the server is accessible?

string ourPostData = "{\"Name\": \"Jack\", \"Score\":3455, \"Character\": \"Bob\" }";

	Hashtable headers = new Hashtable();
	headers.Add("Content-Type", "application/json");
	headers.Add("Cookie", "Our session cookie");
	byte[] pData = Encoding.ASCII.GetBytes(ourPostData.ToCharArray());
	WWW www = new WWW("http://localhost:8082/test", pData, headers);

yield the www variable, when it’s complete and a response is ready to go, the code will continue after the yield statement.

First example of the WWW.WWW from Unity docs.

From the docs:

After the stream is created you have to wait for it to complete, then you can access the downloaded data. As a convenience the stream can be yielded, so you can very easily tell Unity to wait for the download to complete.

yield return www;

if(!String.IsNullOrEmpty(www.error)) {
    // If www.error is instantiated or has some string information in it, an error occurred.