Wednesday, July 4, 2012

AJAX : GET/POST FORM Submit with Drop Down Menu


Lets start from view:
Drop Down Menu In your JSP/HTML

<select id = "Language" onchange="javascript:AjaxEx.sendAjaxRequest();">

<option value ='en'>EN</option>

<option value ='fr'>FR</option>

</select> 


AJAX code that reqired to be include in the view
(function() {
 AjaxEx = {
  init: function(url, elId) {
   if (!url || !elId) {
    alert("Invalid input!");
    return;
   }
   this.url = url;
   var el = document.getElementById(elId);
   if (!el) {
    alert("Container Element, to place Ajax response doesn't exists!");
    return;
   }
   this.el = el;
   this.sampleHtml = "

This will be replaced with AJAX response!

"; // create xml http request object for AJAX requests this.xmlHttp = this.initXmlHttp(); }, // End of init() initXmlHttp : function () { if (window.XMLHttpRequest) // Firefox, Opera, IE7, etc. return new XMLHttpRequest(); if (window.ActiveXObject) // IE6, IE5 return new ActiveXObject("Microsoft.XMLHTTP"); }, // End of initXmlHttp() resetContent : function () { this.el.innerHTML = this.sampleHtml; }, // End of resetContent() sendAjaxRequest : function () { // initialize XML Http object if not available if (!this.xmlHttp) this.xmlHttp = this.initXmlHttp(); if (this.xmlHttp) { var ajaxObj = this; this.xmlHttp.onreadystatechange = function() { if (ajaxObj.xmlHttp.readyState==4 && ajaxObj.xmlHttp.status==200) { // 4 = "loaded", 200 = "OK" ajaxObj.el.innerHTML = ajaxObj.xmlHttp.responseText; } }; var selBox = document.getElementById("Language"); // prepare parameters var langSalect = selBox.options[selBox.selectedIndex].value; if (langSalect == "") { alert("Please select language!"); return; } var params = "langSalect=" + langSalect; // for multiple parameters separate them by '&' as given below // var params = "empCode=E1001&dept=TestDept" this.makePOSTRequest(params); // this.makeGETRequest(params); } else alert("Your browser does not support AJAX."); }, // End of sendAjaxRequest() makePOSTRequest : function (params) { this.xmlHttp.open("POST", this.url, true); //Send the proper header information along with the request this.xmlHttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); this.xmlHttp.setRequestHeader("Content-length", params.length); this.xmlHttp.setRequestHeader("Connection", "close"); this.xmlHttp.send(params); }, // End of makePOSTRequest() makeGETRequest : function (params) { this.xmlHttp.open("GET", this.url + "?" + params, true); this.xmlHttp.send(null); } // End of makeGETRequest() } // End of AjaxEx })();

Create Your AJAX content object as fallows for submission of the perticular url and the tag id whose content need to be set Asynchronously

<script type="text/javascript">

<var url = "...../DBServlet">

<var ajaxObj = document.getElementById('.....')>

<AjaxEx.init(url, "ajaxObj">

</script>


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