<!DOCTYPE html>
<html>
<head>
<title>Lesson 18: Making AJAX Calls</title>
</head>
<body>
<h1>Lesson 18: Making AJAX Calls - Plain Text Response</h1>
<div>
<h2 id="myHeader">Click the button to call your data</h2>
<input type="button" value="Click Me!" onclick="getText('test.txt')" />
</div>
<script type="text/javascript">
var myRequest;
function getText(url)
{
if (window.XMLHttpRequest)
{
myRequest = new XMLHttpRequest();
}
else
{
myRequest = new ActiveXObject("Microsoft.XMLHTTP");
}
myRequest.open("GET", url, true);
myRequest.send(null);
myRequest.onreadystatechange = getData;
}
function getData()
{
var myHeader = document.getElementById("myHeader");
if (myRequest.readyState ===4)
{
if (myRequest.status === 200)
{
var text = myRequest.responseText;
myHeader.firstChild.nodeValue = text;
}
}
}
</script>
</body>
</html>
This code is from this tutorial: http://www.html.net/tutorials/javascript/lesson18.php
Questions:
what does this mean: myRequest.send(null); what is the difference between it and myRequest.send();?
No difference. .send(null) is mean that you are sending "null" content in request body. .send() is mean that you are sending nothing in request body. In case of GET requst there is no difference, becouse request body is not sending. In case of POST request there will be none difference too.