How can I extract a form's data at the server?

I have a form and want to submit its contents to the server on submission.I found a similar question here1 which suggests using a POST request but I am not sure how to do that. Here's my code Client side:

<form method='post' action='http://localhost:8080' >
  <textarea id='chatHistory'></textarea>
  <br/><br/>
  <div class="demo">
   <div class="ui-widget"> 
    <input id="tags" size="50" type="text" />
    <input type="submit" value="Send" style="height:40px;width:120px;font-size:18px;" />
   </div>
  </div>
 </form>     

Server Side:

app.post('/', function(req,res)
{
  // create reusable transport method (opens pool of SMTP connections)
  var smtpTransport = nodemailer.createTransport("SMTP",{
    service: "gmail",
    auth: {
      user: "my_mail_id@gmail.com",
      pass: "password"
    }
});

// setup e-mail data with unicode symbols
var mailOptions = {
 from: "Suggestion Box ✔ <my_mail_id@gmail.com>", // sender address
 to: "receiever@gmail.com", // list of receivers
 subject: "Hello ✔",
 text: req.chatHistory.value
};
// send mail with defined transport object
smtpTransport.sendMail(mailOptions, function(error, response){
 if(error){
     console.log(error);
 }else{
     console.log("Message sent: " + response.message);
 }
});
});

The body of the mail is not getting filled with the value from the client.I think the problem is here:req.chatHistory.value

How can I get the chatHistory value at the server side?