How to call or make the javascript function from the Application_Start of global.asax in asp.net mvc(C#) application?
6
-
What are you trying to achieve?Lazarus– Lazarus2009-10-21 11:39:00 +00:00Commented Oct 21, 2009 at 11:39
-
The javascript function gets the data to be shown to the User from database through jquery. The javascript function will be executed periodically using setTimeout. I need to call this javascript function only once (not in $(document).ready), so that the setTimeout will take care of calling it again periodicallyPrasad– Prasad2009-10-21 11:43:38 +00:00Commented Oct 21, 2009 at 11:43
-
1Whats wrong with calling SetTimeout in $(document).ready ?LiamB– LiamB2009-10-21 11:44:29 +00:00Commented Oct 21, 2009 at 11:44
-
its gets reset when i move from first to second page.Prasad– Prasad2009-10-21 11:48:45 +00:00Commented Oct 21, 2009 at 11:48
-
@Prasad - that's standard behaviourRuss Cam– Russ Cam2009-10-21 12:11:05 +00:00Commented Oct 21, 2009 at 12:11
|
Show 1 more comment
4 Answers
You can remember the last "invoked" time in Session or cookies (which is easier for javascript but worse for performance/etc) and then
function check() {
// or var lasttime = <%= Session["lasttime"] %>;
if (now - $.cookie("lasttime") > timeout)
{
$.cookie("lasttime", now);
performAction();
}
window.setTimeout(check, 1000);
}
You can call time function once from $(document).ready().
But note that it may take browser several seconds to render page, or it may bump into 404 or other errors and page will be inactive... javascript is not a reliable way to do scheduled actions.
Another way is to have your timer on server. JavaScript function like above will just ask for it from time to time, passing user ID or something like that. This will prevent timer reset during page reload. But you'll have to do request too often. So the best solution would be to combine two techniques:
- Run timer on server
- When page is renders, set var inited = false;
- Run function above but like this: if (!inited) timer = $.getJSON("/timer?uid=x"); and when you have the precise current timer you can continue with JavaScript only, without server requests.
3 Comments
Funka
I like and agree with this answer. If the goal is to prevent some javascript function from being called more than once per minute regardless of how many separate pages the user clicks around during that time, then having javascript be responsible (through a cookie, as shown) for keeping track of the time it last ran makes the most sense. You could use a Session var (which most likely relies on cookies anyway), sure, but you'll just end up injecting it back into the script. Only thing I'm not sure of, is your comment that doing this in javascript cookies is worse for performance?
Funka
Actually, the only thing to watch out for might be if the user has open multiple tabs/windows, to make sure they are not all competing for the timer!
queen3
Cookies are sent with each requests, even for static files. Yes session relies on cookies (usually) but there's single one; if you add more this increases traffic a bit. And user can switch cookies off. As for multipage, this is where combined client-server solution makes sense... as there'll be always single instance of the timer on the server - which can be contacted once or periodically to check the timer.
"The javascript function gets the data to be shown to the User from database through jquery. The javascript function will be executed periodically using setTimeout"
This wouldnt be the place to do it.
Have you thought about using your masterpage?
4 Comments
Prasad
i am using this call in master page now. But its keeps resetting the interval everytime i navigate to the other page. Say i need to call the js function every 1 minute, when i navigate from first to second page, the interval gets reset and i need to wait 1 minute in that page for the js function to get call
LiamB
Thats the nature of the web. Each page is independant. Btw, If I were you I'd use a session to keep track of the time the user turned up at the page. Then use some logic to check the current time vs the session time and then if it breaches 1 min output an alert script (Or whatever you like)
Mathias F
You should call the function once on $(document).ready) and also via setTimeout. Then it gets called in second 1 and in 60/120/180
LiamB
@Mathias Fritsch - he allready stated he's switching between pages. SO that will not work.
Since JavaScript executes on client side and global.asax executes on server side. You cannot do that.
4 Comments
LiamB
I think he was looking for a way to dump it to the page a bit like RegisterClientScript
Çağdaş Tekin
@Pino, he says he wants to call the JS function, in both the question and in the comments.
Çağdaş Tekin
@Prasad, Response object won't be ready on Application_Start(), so you can't output anything in there.
LiamB
See my post about using the Session to track it. I did this about a year ago, however it got a bit messy. I ended up using a seperate web-app to track it and called that app from the main website.
How about you check a Application level variable at the load of your landing page (master page would also do) and register whatever the javascript there and set the variable.
You can skip the registration if the variable is set.
Comments
