Do a POST request, redirecting the current page to the result.

post.js

function post(url, values) {
  function add_input(name, value) {
    var input = document.createElement("input");
    input.name = name;
    input.value = value;
    form.appendChild(input);
  }
  
  var form = document.createElement("form");
  
  Object.keys(values).forEach(function (name) {
    value = values[name];
    add_input(name, value);
  });
  
  form.submit();
}