var last_id = 0; function searchDirectory() { var input = document.getElementById("search").value; if(input){ last_id++; var request_id = last_id; var data = new FormData(); data.append("query", input); var xhttp = new XMLHttpRequest(); xhttp.onreadystatechange = function() { if (request_id != last_id) return; if (this.readyState == 4 && this.status == 200) { var result_div = document.getElementById("search-results"); result_div.innerHTML = xhttp.responseText; } }; xhttp.open("POST", "/directory/search", true); xhttp.send(data); } }