Can I assign an external value to a JS variable?

[Harry Stangel]

Noble reader,

My goal is to obtain the current time on the web server and display it in
the client's browser. I want the server time displayed independent of the
client's current clock setting, but use the client clock to refresh the
displayed time every second. To compensate for drift, I want to
periodically calibrate the page with the server time by refreshing the page,
say every ten minutes or so.

I have a servlet '/apps/clock' that returns the current (server) time as
XML, i.e.

<milliseconds>1086478233003</milliseconds>

I can strip away the XML tags with XSLT, leaving the value '1086478233003'.

I need a way to read the value into a JavaScript variable, so I can use it
to create a Date object, increment the variable, etc.

So, does anyone know a way to assign an external value to a JS variable?

Best,
Harry

 

[Ray Morgan]

I have a servlet '/apps/clock' that returns the current (server) time as
XML, i.e.

<milliseconds>1086478233003</milliseconds>

I can strip away the XML tags with XSLT, leaving the value '1086478233003'.

Have the servlet do the stripping server-side, and output the
JavaScript you need. For example, in PHP, it could look something
like:

<?php
# Assume $mil is set to the time in milliseconds via
# microtime() or something similar
print "<script type='text/javascript'>\n";
print "var d = new Date($mil);\n";
print "</script>\n";
?>

When the HTML page loads, you'll have var d set to the value of the
server time.

 

[Harry Stangel]

Okay, I know better than to answer my own post, but I discovered this
method:

var request;
var xml;
var milliseconds;

// Mozilla technique
if (window.XMLHttpRequest) {
request = new XMLHttpRequest();
request.open("POST", TIMEHOST_URL, false); // we POST to ensure
the
// response is not
cached
request.send(null);
xml = request.responseXML;
if (xml) {
milliseconds =
Number(xml.getElementsByTagName("milliseconds").item(0).textContent);
}
}
// IE/ActiveX technique
else if (window.ActiveXObject) {
request = new ActiveXObject("Microsoft.XMLHTTP");
if (request) {
request.open("POST", TIMEHOST, false);
request.send();
xml = request.responseXML;
if (xml) {
milliseconds =
Number(xml.getElementsByTagName("milliseconds").item(0).text);
}
}
}

Peace,
Harry