I found a code for how to send a post to php but i can send only one variable. Here is my code:
Private Sub Button1_Click_1(sender As Object, e As EventArgs) Handles Button1.Click
Dim postData = "msg=" & TextBox2.Text
Dim request As WebRequest = WebRequest.Create("http://localhost/msg.php")
request.Method = "POST"
Dim byteArray As Byte() = Encoding.UTF8.GetBytes(postData)
request.ContentType = "application/x-www-form-urlencoded"
request.ContentLength = byteArray.Length
Dim dataStream As Stream = request.GetRequestStream()
dataStream.Write(byteArray, 0, byteArray.Length)
dataStream.Close()
End Sub