[removed] sending custom parameters with window.open() but its not working

Answer 1

To concatenate strings, use the + operator.

To insert data into a URI, encode it for URIs.

Bad:

var url = "http://localhost:8080/login?cid='username'&pwd='password'"

Good:

var url_safe_username = encodeURIComponent(username);
var url_safe_password = encodeURIComponent(password);
var url = "http://localhost:8080/login?cid=" + url_safe_username + "&pwd=" + url_safe_password;

The server will have to process the query string to make use of the data. You can't assign to arbitrary form fields.

… but don't trigger new windows or pass credentials in the URI (where they are exposed to over the shoulder attacks and may be logged).