handle onchange in php code example

Example 1: js select on change value

document.getElementById('my-select').addEventListener('change', function() {
  console.log('You selected: ', this.value);
});

Example 2: javascript add function to onchange event

transport_select.setAttribute("onchange", function(){toggleSelect(transport_select_id);});
// or
transport_select.onchange = function(){toggleSelect(transport_select_id);};