Front-end: Calling the back-end

var xhr = null;

// This will be called when the request is complete
function processXHR() { … }

function update_table() {
  // Should check for existing xhr connection
  
  // For IE you'd use ActiveXObject("Microsoft.XMLHTTP")
  xhr = new XMLHttpRequest();
  xhr.onreadystatechange = processXHR;

  // the 'this' variable refers to the text-field in this case
  var url = '/api/contacts/search?term=' + escape(this.value);

  xhr.open('GET',url,true);
  xhr.send(null);
}