AJAX example
To help you understand how AJAX works, we have created a small AJAX application:
Example
<html><!DOCTYPE html>
<html>
<head>
<script>
function loadXMLDoc()
{
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("myDiv").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","/try/ajax/ajax_info.txt",true);
xmlhttp.send();
}
</script>
</head>
<body>
<div id="myDiv"><h2>使用 AJAX 修改该文本内容</h2></div>
<button type="button" onclick="loadXMLDoc()">修改内容</button>
</body>
</html>Run instance»
Click the "Run instance" button to view the online instance
AJAX instance analysis
Above The AJAX application contains a div and a button. The
div section is used to display information from the server. When the button is clicked, it is responsible for calling a function called loadXMLDoc():
<!DOCTYPE html>
<html>
<body>
<div id="myDiv"><h2>Let AJAX change this text</h2>< ;/div>
<button type="button" onclick="loadXMLDoc()">Change Content</button>
</body>
</html>
<html>
<body>
<div id="myDiv"><h2>Let AJAX change this text</h2>< ;/div>
<button type="button" onclick="loadXMLDoc()">Change Content</button>
</body>
</html>
Next, add a <script> tag to the head section of the page. This tag contains the loadXMLDoc() function:
<head>
<script>
function loadXMLDoc()
{
.... AJAX script goes here ...
}
</script>
</head>
<script>
function loadXMLDoc()
{
.... AJAX script goes here ...
}
</script>
</head>
The following chapters will explain to you how AJAX works.
