I am working on an ajax web page which has several controls including a ScriptManager control and the ajax Timer control. When the timer fires a tick I want the server side to perform some calculations and then call a client script function with the results. The client script will then do something with the results.
Also, I want to call another javascript function when I click a button.
I'm a bit rusty with javascript, so I'd like to see examples on how to make this work.
What and where exactly you want to do?When the timer fires, I want the server to generate (calculate) a pair of integers (or possibly an array of pairs) and call a javascript function on the client side passing those numbers. The client will then "plot" points on a graphics window using some built-in drawing java functions I have. The timer will probably fire several times a second. The client does not need to make any calls to the server.
When a button is clicked, I want the server to call another javascript function (passing no arguments) which will erase the graphics window. The timer continues firing.
I have other buttons, to start and stop the timer, sliders to change the timer rate and other parameters, checkboxes and radio buttons which also affect the calculations, etc. All I need help with is making the client calls and passing the data. Is the ScriptManager useful in that respect? By the way, I'm kind of "new" in java.
I've seen scenarios where client calls server, and server calls the client back with a reply. However, can the server just call the client repeatedly? Or does the timer control act as the client-to-server caller?
Yo can use for calling javascript function
Registering Custom Script
from ScriptManager
http://ajax.asp.net/docs/mref/O_T_System_Web_UI_ScriptManager_RegisterClientScriptBlock.aspx
For calling server side function use web services..
Actually, what I need to do requires "COMET", a form of "reverse AJAX". Is there an easy way to emplement COMET in ASP.Net? When the user clicks the "start" button, the server needs to begin "firing" pairs of numbers at the client at a steady rate (several times a second) until the user clicks the "stop" button.
Hi,
According to theclient life cycle, you can hook an event handler to theloadevent which will be fired every time an partial postback returns. Then invoke your graphical jscript function in it. For instance:
<%@. Page Language="C#" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"
<script runat="server"
</script
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager
</div>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:Timer ID="Timer1" runat="server" Interval="1000">
</asp:Timer>
</ContentTemplate>
</asp:UpdatePanel>
<input id="time" />
</form
<script type="text/javascript">
function draw(){
var dt = new Date();
$get("time").value = dt.toString();
}Sys.Application.add_load(ApplicationLoadHandler)
function ApplicationLoadHandler(sender, args)
{
draw(); // invoke your graphical function instead
}
</script
</body>
</html>
Thanks, but I didnt get it what does this do ?
<script type="text/javascript">
function draw(){
var dt = new Date();
$get("time").value = dt.toString();
}Sys.Application.add_load(ApplicationLoadHandler)
function ApplicationLoadHandler(sender, args)
{
draw(); // invoke your graphical function instead
}
</script>
This is a javascript function with no usefulness at all, just for demostration purpose. You need to invoke what you really need here.
I need the server to send a pair of numbers to the client each time it fires.
You can expose the method of sending numbers as a web service on the server.
Then invoke it at client side.
Please read this:
http://ajax.asp.net/docs/tutorials/ConsumingWebServicesWithAJAXTutorial.aspx
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