Ajax Example in coldfusion
<script type="text/javascript"> function showvalues(str) { var xmlhttp; if (window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, Safari xmlhttp=new XMLHttpRequest(); } else {// code for IE6, IE5 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } xmlhttp.onreadystatechange=function() { if (xmlhttp.readyState==4 && xmlhttp.status==200) { document.getElementById("txtHint").innerHTML=xmlhttp.responseText; } } xmlhttp.open("GET","?city_name="+str,true); xmlhttp.send(); } </script> <cfparam name="url.city_name" default=""> <div id="txtHint">City info will be listed here... <cfform> <cfselect id="city_name"