Develop Reference

Ajax with Javascript to send text to html

I am learning ajax with javascript where I have a html which has a button inside a div like below
home.html
<div id="test">
<h1>Welcome</h1>
<button type="button" onclick="loadDoc()">Show</button>
</div>
On clicking on the button I would like to update the with sample text lets say Hai ! Ajax here
function loadDoc() {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
document.getElementById("test").innerHTML = xhttp.responseText;
}
};
xhttp.open("POST", "ajax_info.txt", true);
xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xhttp.send();
}
If I do with opening a text file which contains the text and send on http request it works but I do not want to load a file in my open() method instead just send text to my home.html and I tried like below does not seems working
xhttp.open("POST", "home.html", true);
xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xhttp.send("message=Hai Ajax Here");
How to do this ?
Thanks

Replace InnerHTML With Cookie Logging

I've got some javascript code for replacing innerHTML of a element when clicked. Now i've got the code for that and it does work great! But one small issue is that, I want the webserver to remember the change when innerHTML of an element was replaced. So the webserver remembers the change and doesn't return to its default state. Whether with database or in Cookie, sessionStorage, localStorage.
document.getElementById("replace1").innerHTML = localStorage.getItem("replace1");
function loadDoc() {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
localStorage.setItem("replace1",this.responseText);
}
};
xhttp.open("GET", "https://natevanghacks.com/replacements/yoinkexecutor2.html", true);
xhttp.send();
}

Try something like this in AJAX:
localStorage.setItem("replace1",this.responseText);
And after body onload:
document.getElementById("replace1").innerHTML = localStorage.getItem("replace1");
Edit:
function loadSavedData(){
var data=localStorage.getItem("replace1");
document.getElementById("replace1").innerHTML = data?data:'No Data found';
}
function deleteData(){
localStorage.removeItem("replace1");
}
function loadDoc() {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
localStorage.setItem("replace1",this.responseText);
document.getElementById("replace1").innerHTML =this.responseText;
console.log(this.responseText);
}
};
xhttp.open("GET", "filename.html", true); //put your filename here...
xhttp.send();
}
<button onclick="loadDoc()">Send request and load Data
</button>
<button onclick="loadSavedData()">load Saved Data
</button>
<button onclick="deleteData()">Delete saved Data
</button>
<br>
<div id="replace1">
</div>
Note: You should run this file on http:// or https:// protocols only

Load clicked URLs from AJAX loaded page

I have the following code which fetches content from another page using AJAX:
<div id="content">
</div>
<script>
function loadDoc() {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
document.getElementById("content").innerHTML =
this.responseText;
}
};
xhttp.open("GET", "/Home/", true);
xhttp.send();
}
</script>
It works! Sadly, when you click on an URL from that page, all of the already loaded code disapears. :(
So my question is:
How can I make the clicked URLs load inside my DIV (content)?
Cheers.

XHTTP request from REST API

I have this API
[HttpGet("data")]
public dynamic GetData(){
return context.DataTable.ToList();
}
I tried calling it on my Javascript using this snippet;
function getData(){
var xhttp = XMLHttpRequest();
xhttp.open("GET", "api/myclass/data", true);
xhttp.setRequestHeader("Content-type","application/json");
xhttp.send();
var resp = xhttp.responseText;
}
However, it only returns empty XMLHttpRequest.
I think what's wrong there is the URL. How I may able to call the API to my Javascript?

Since u have not cheked the response of ur answer, i susspect there is something wrong in ur backend. But, here is a sample of functional solution:
<!DOCTYPE html>
<html>
<body>
<h2>Using the XMLHttpRequest Object</h2>
<div id="demo">
<button type="button" onclick="loadXMLDoc()">Change Content</button>
</div>
<script>
function loadXMLDoc() {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
console.log("Status is: "+this.status);
if (this.readyState == 4 && this.status == 200) {
document.getElementById("demo").innerHTML =
this.responseText;
}
};
xhttp.open("GET", "xmlhttp_info.txt", true);
xhttp.send();
}
</script>
</body>
</html>
You van find more info here. But in the line
xhttp.open("GET", "api/myclass/data", true);
The second parameter is the address of a file in ur server. r u sure u have wrotten the correct format? what is the extension of ur data file.
I guess, both backend and front end should be reconsidered. To do it:
Try to send a reuqest using postman to backend
in frontend check the status of response using my answer
To make sure make it async = false with
xhttp.open("GET", "api/myclass/data", false);
Therefore, there wouldn't be a delay as #Alex Kudryashev pointed
Solution:
You need to first find the result of line
console.log("Status is: "+this.status);
in ur browser's console.
If u get the responseText as empty it may come because u have sent an empty string from backend,(we are not sure because u have not tested ur backend with postman) but it is crucial to know the status of response.

The request may take time to receive the response so you have to wait. Something like this.
function getData(){
var xhttp = XMLHttpRequest();
xhttp.open("GET", "api/myclass/data", true); //the request is asynchronous
xhttp.onreadystatechange = function(){
if(this.readyState == 4 && this.state == 200){ //**this** is xhttp
//data are received and ready to use
var resp = this.responseText;
//do whatever you want with resp but never try to **return** it from the function
}
}
xhttp.setRequestHeader("Content-type","application/json");
xhttp.send();
//var resp = xhttp.responseText; //too early ;(
}

Basic AJAX script not working

I'm trying to load a file and display it in the div section of my web page, using AJAX. The console output shows that the XMLHttpRequest object is successfully created, but then nothing happens: the callback function is never called and the content of the URL is not fetched.
<body>
<div id="demo"><p>Some text</p></div>
<button type="button" onclick="loadDoc()">Request URL</button>
<script>
function loadDoc() {
var xhttp;
if (window.XMLHttpRequest) {
xhttp = new XMLHttpRequest();
console.log('object created'); // this message is printed
} else if (window.ActiveXObject) {
xhttp = new ActiveXObject("Mіcrosoft.XMLHTTP");
}
xhttp.onreadystatechange = function() {
console.log('inside callback function'); // this message is never printed
if(xhttp.readyState == 4 && xhttp.status == 200) {
document.getElementById("demo").innerHTML = xhttp.responseText;
}
xhttp.open("GET", "http://tools.ietf.org/rfc/rfc6120.txt", true);
xhttp.send(null);
};
}
console.log('end of script'); // this message is printed
</script>
</body>
I don't know much about HTTP requests and I'm assuming that AJAX can be used to load an url that is perfectly accessible to my web browser.
Is this assumption incorrect? If not, then what am I doing wrong?

Reorder your code
xhttp.onreadystatechange = function() {
console.log('inside callback function');
if(xhttp.readyState == 4 && xhttp.status == 200) {
document.getElementById("demo").innerHTML = xhttp.responseText;
}
};
xhttp.open("GET", "http://tools.ietf.org/rfc/rfc6120.txt", true);
xhttp.send(null);
You must to send the request and the callback will be fired automatically. If you put that code inside the callback, you never achieve the request to the txt file