Performing an AJAX call from JS in asp.net MVC without Jquery - asp.net-mvc

Question

I am developing an app that will be used on an old WInCE devices where IE Embedded doesn't support Jquery, which is why I can use it. So, my question is, what is the way to perform an AJAX call from within a js file.
Code:
html
#using (Html.BeginForm("", "SomeAction", FormMethod.Post, new { id = "myId" }))
{
input field 1: <input type="text" name="somename1"><br>
}
What I need to do is call a validate routine and return a string when the user clicks enter on the somename1 input field.
Normally, this would be done with Jquery, so how do I do it without only utilizing what the MVC asp has to offer (again, the ajax might not work at all on the old browser, but I would like to give it a shot and avoid refreshing the whole page).

Answer 1

Step 1: Get a XMLHttp Object using:
function getXMLHttpRequest() {
var xmlHttpReq = false;
// to create XMLHttpRequest object in non-Microsoft browsers
if (window.XMLHttpRequest) {
xmlHttpReq = new XMLHttpRequest();
} else if (window.ActiveXObject) {
try {
xmlHttpReq = new ActiveXObject("Msxml2.XMLHTTP");
} catch (exp1) {
try {
// to create XMLHttpRequest object in older versions
// of Internet Explorer
xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
} catch (exp2) {
xmlHttpReq = false;
}
}
}
return xmlHttpReq;
}
Then do this (Just an example for downloading a file ajax request)
function myFunction(){
var xmlHttpRequest = getXMLHttpRequest();
xmlHttpRequest.onreadystatechange = getReadyStateHandler_download_file(xmlHttpRequest,file_indicator);
xmlHttpRequest.open("GET", "/wasa-app/DownloadServlet?pmuId="+pmuID+"&dlDate=" + formatted_date+"&check_flag=1"+"&file_indicator="+file_indicator, true);
xmlHttpRequest.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
xmlHttpRequest.send(null);
}
function getReadyStateHandler_download_file(xmlHttpRequest, fileIndicator) {
return function() {
if (xmlHttpRequest.readyState == 4) {
if (xmlHttpRequest.status == 200) {
populateSchedule();
var resp = xmlHttpRequest.responseText;
if (resp == ""){
document.getElementById("save_" + fileIndicator).disabled = false;
document.getElementById("message").innerHTML = "";
}
else{
document.getElementById("save_" + fileIndicator).disabled = true;
document.getElementById("message").innerHTML = xmlHttpRequest.responseText;
}
} else {
alert("HTTP error -- " + xmlHttpRequest.status + ": " + xmlHttpRequest.statusText);
}
}
};