AJAX Tutorial: Saving Session Across Page Loads Without Cookies, On The Client Side
<html>
<head>
<script language="JavaScript">
function initialize() {
if (sessionExists() == false) {
saveState("Hello World 1");
// some browsers need a bit of a timeout
window.setTimeout("saveState('Hello World 2')", 300);
window.setTimeout("saveState('Hello World 3')", 600);
}
}
function getIFrameDocument() {
var historyFrame =
document.getElementById("historyFrame");
var doc = historyFrame.contentDocument;
if (doc == undefined) // Internet Explorer
doc = historyFrame.contentWindow.document;
return doc;
}
function sessionExists() {
var doc = getIFrameDocument();
try {
if (doc.body.innerHTML == "")
return false;
else
return true;
}
catch (exp) {
// sometimes an exception is thrown if a
// value is already in the iframe
return true;
}
}
function saveState(message) {
// get our template that we will
// write into the history iframe
var templateDiv =
document.getElementById("iframeTemplate");
var currentElement = templateDiv.firstChild;
// loop until we get a COMMENT_NODE
while (currentElement &&
currentElement.nodeType != 8) {
currentElement = currentElement.nextSibling;
}
var template = currentElement.nodeValue;
// replace the templated value in the
// constants with our new value
var newContent =
template.replace(/\%message\%/, message);
// now write out the new contents
var doc = getIFrameDocument();
doc.open();
doc.write(newContent);
doc.close();
}
</script>
</head>
<body onload="initialize()">
<div id="iframeTemplate">
<!--
<html>
<body>
<p>%message%</p>
</body>
</html>
-->
</div>
<iframe id="historyFrame"></iframe>
</body>
<html>
<head>
<script language="JavaScript">
function initialize() {
if (sessionExists() == false) {
saveState("Hello World 1");
// some browsers need a bit of a timeout
window.setTimeout("saveState('Hello World 2')", 300);
window.setTimeout("saveState('Hello World 3')", 600);
}
}
function getIFrameDocument() {
var historyFrame =
document.getElementById("historyFrame");
var doc = historyFrame.contentDocument;
if (doc == undefined) // Internet Explorer
doc = historyFrame.contentWindow.document;
return doc;
}
function sessionExists() {
var doc = getIFrameDocument();
try {
if (doc.body.innerHTML == "")
return false;
else
return true;
}
catch (exp) {
// sometimes an exception is thrown if a
// value is already in the iframe
return true;
}
}
function saveState(message) {
// get our template that we will
// write into the history iframe
var templateDiv =
document.getElementById("iframeTemplate");
var currentElement = templateDiv.firstChild;
// loop until we get a COMMENT_NODE
while (currentElement &&
currentElement.nodeType != 8) {
currentElement = currentElement.nextSibling;
}
var template = currentElement.nodeValue;
// replace the templated value in the
// constants with our new value
var newContent =
template.replace(/\%message\%/, message);
// now write out the new contents
var doc = getIFrameDocument();
doc.open();
doc.write(newContent);
doc.close();
}
</script>
</head>
<body onload="initialize()">
<div id="iframeTemplate">
<!--
<html>
<body>
<p>%message%</p>
</body>
</html>
-->
</div>
<iframe id="historyFrame"></iframe>
</body>
<html>
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