app.js

var express = require('express');
var app = express();
var port = process.env.PORT || 9292;

app.get('/', function(req, res) {
    res.render('index');
});

app.post('/control/:action', function(req, res) {

  var action = req.params.action;
  
  // do something
  res.json({ success: true })
  
});


app.listen(port);

index.html

<button data-action="start">Start</button>
<button data-action="stop">Stop</button>
<button data-action="reverse">Reverse</button>

<script>
  
  // Let's assume jquery....
  
  $('button').click(function(e) {

    e.preventDefault();
    
    var action = this.getAttribute("data-action")
    
    $.post("/control/" + action, function(data) {
      console.log(data);
    })
    
  })
  
</script>