I've heard different stories about ASP.NET and JavaScript: that it works fine with Javascript turned off, that only some parts don't work, and that nothing works at all.
How exactly are ASP.NET applications affected if JavaScript is turned off in a client's browser? What parts don't work (if any)?
For example, will RequiredFieldValidators still work? What about UploadControls? AJAX UpdatePanels and AsyncPostBack's? FileUploads? Do page codebehinds still run?
Forgive my ignorance, I can't seem to find much about the issue that is in-depth.
Client-side validation and Ajax won't work, including async postbacks and any control that requires Javascript in order to work.
Server-side validation (which should always happen anyway) and full postbacks and such should always work, and i think a FileUpload control will as well. The biggest difference would be that someone wouldn't see that the data they entered happened to be invalid til the form was submitted.
LinkButtons don't work because they render out a javascript: target.
If you use GridView controls with ButtonColumns then these won't work as the buttons are javascript too. One way around this is to use a TemplateColumn and add <asp:Button> objects inside it.
Also GridView paging and sorting is JavaScript out-the-box so you'd have to write custom paging and sorting.
Also any control with AutoPostback set to true (e.g. a DropdownList) will not auto-postback. You will be able to catch the SelectedIndexChanged but ONLY when the next postback happens.
Any control that "does something" on the client side without a full page request going back to the server(ie. the whole page reloading) is done via JavaScript , and will not work with JavaScript turned off.
Remember HTML is static, so anything that "changes" in the browser window other than CSS hover effects or anything that calls back to the server without a full page reload, is done via JavaScript, and you cannot expect that to work with JavaScript disabled on the client.
Related
Is there a straightforward way to use server-side validation with ASP.NET's validation controls in a form that's displayed in a modal dialog? I am using jQuery and SimpleModal (in C#, VS2010, .NET 4.0)
I've got a modal form which works fine. I need to use a server-side validation because the logic depends on data specific to the record being accessed
My solution for the project I'm working on now is to use a jQuery ajax call to pass all the form data to the server and get back the validation results before allowing the post to proceed. But this is relatively time consuming to implement, and in some situations I'm dealing with now all the validation code exists already.
The first challenge is that of course the modal dialog will close on a full postback. So you could put an UpdatePanel inside the dialog... without even thinking about this too much, though, I assumed that it wouldn't work out that well. It doesn't. And the form which opens the modal dialog to begin with is already in an UpdatePanel, which further confuses matters.
Anyway, I tried putting the contents of the modal form in an UpdatePanel for the heck of it. It does actually do a partial postback, the dialog remains open, but the contents of the dialog do not get updated with anything I change server side. If I close and re-open the dialog on the same page after testing the validation code, though, its contents are in fact updated to reflect these changes. Obviously the way the dialog is rendered is confusing ASP.NET. Or vice-versa. But this just seems sketchy from the get-go.
Rather than trying to hack my way through this problem I was hoping that others had some suggestions about a better way to approach this. Or just tell me I'm trying to hard too mix apples and oranges and I should keep it all client side (or client side + jQuery ajax) if that is the only sensible thing to do.
The two approaches I've taken:
1) submit the data via ajax, the response includes a success:true or false. If false, there is a message included that details the issue.
2) submit the form normally. If there is a validation problem, but the errors in a hidden div on the page and write JS to check for content in that div when the page loads and display the warning/error as necessary.
I currently have a simple form that when you click the "save" button will persist it to the database.
I would like to use JQuery to do the callback for me and popup a "Save completed" div window/div of some sort.
My only problem is how do I call the btnSave_Click() event from JQuery?
If I use PageMethods the method would have to be static and therefore lose access to my textboxes and other page controls?
Thanks,
Goosey
Are you explicitly trying to avoid passing the values of the input controls? because that would be much easier.
Using a lightweight jQuery call to do the post but then expecting a full control hierarchy in the code behind to pull data out? What's the intent here? If you require that, it would probably be easier just to submit the page, and register javascript to run to pop the success message up on load.
Personally, I think the page method route and $.ajax or $.post is a much cleaner, separate way to solve the issue. That way you can just show the popup as part of the success callback.
You can use onClientClick
Have a look at the jQuery Form Plugin, it can change existing forms into Ajax forms.
You need to set __EVENTTARGET to the id of the control that you want to simulate causing the postback if you want to use the same handler. I seem to recall having to replace the underscores with dollar signs as well, but I could be wrong on that. The hidden inputs, __EVENTTARGET and __EVENTARGUMENT, are used by the framework to identify which control caused the postback. There's a nice discussion of the server side issues in this blog post, though it doesn't talk about AJAX. Google for __EVENTTARGET and postback for more info.
Ok, so the problem is as follows: I'm using jQuery's AJAX in order to make behind the scene calls within the page (on events such as voting an item) and changing the content in the appropriate element. The problem occurs when I mix AJAX with ASP.net's AJAX, more precisely when I try to do a postback AFTER I've used jQuery on the page to perform an action. The page's viewstate is changed and validation fails (which would seem somewhat normal as a matter of fact).
My question is: can I disable the validation somehow so that I can perform postbacks combined with the chaged page viewstate? So far searching on how to disable it yielded no results.
A more practical example is on a comments page where I allow voting the comments and posting new comments as well. So should a user vote a comment and THEN post his own, the page's contents is changed, and thus validation fails. Also, I've tried placing the comment form within an update panel as to prevent the entire page from posting, but it still fails.
Of course I could use an alternate route and have a different page for handling the event and just call that via jQuery's AJAX, but I was wondering if I could do this by combining ASP.net and jQuery.
Thanks in advance.
If you want to disable viewstate verification, you can set it at the page or config level by using Page.EnableViewStateMac = false.
http://msdn.microsoft.com/en-us/library/system.web.ui.page.enableviewstatemac.aspx
It's not necessarily a good idea though because the validation functionality is there to protect from viewstate tampering, which you'll be turning off...
If you're running into issues with invalid viewstate because of jQuery ajax calls, one option is to consider using the Ajax controls, such as the UpdatePanel. You can wrap certain controls and mark the UpdatePanel as conditional to ensure a small round trip. This will not interfere with viewstate and allow you to continue to use viewstate validation and ajax at the same time.
There may be ways to use jQuery ajax calls and not interfere with viewstate validation. Others may be able to highlight this approach.
I need the ability to temporarily turn off the partial page update behavior for an ASP.NET Ajax / UpdatePanel based page. (The reason is to circumvent the issue where IE blocks "automatic file downloads" for downloads generated as a result of this postback, but I don't want to distract from my original question)
I looked at the client side javascript libraries hoping to find a switch somewhere. I think a solution might involve using javascript to override the 'onclick' event handler for the control that acts as the trigger, and then calling "submit" on the form itself..
Also, using the EnablePartialRendering property on the server-side ScriptManager control won't work because that is done when the page is being built. I need to be able to do this as a result of switching a drop down list box.
Any ideas?
Cheers!
/ Sean
Well, after much trial and error, I found two approaches that seemed to work:
Use Javascript to manually submit the top level form associated with the page. This usually has the ID of "form1".
Create a button that is outside of any UpdatePanels and use Javascript to click the button.
I wound up using the second approach, since it allowed me to handle the event with a specific routine without the need to guess that my postback came from a Javascript call.
This is an example of the code that performed the postback:
...
if (isDownload) {
document.getElementById('FullPostbackSubmitter').click();
return;
}
...
Hope this helps someone else!
You can set the EnablePartialRendering property of your ScriptManager to false.
On a rather complicated screen with a big updatepanel, I'm running into the following problem:
If a user clicks on a certain button 6 or 7 times really fast, it seems to eventually process the last request out of turn and problems occur. Specifically, there's an xml document in session state, and it gets out of sync.
What I really want to do is block clicks to this button until the postback completes. I know I could probably find an easy way to do this with Javascript, but it seems like it might be built-in.
Any thoughts?
Note: The answers below are helpful, but they haven't solved the problem. After disabling the linkbutton with onClientClick and then allowing it to come back after the postback enabled again, the problem persists. It's almost as if the updatepanel isn't quite done with everything even though it has drawn the fresh, enabled linkbutton on the screen.
More notes (solved!): I solved this one by using BlockUI (jQuery plugin). See my answer below.
ASP.NET UpdatePanel always honors the last request. If you make a request while one is processing, the first requests gets terminated and the current one is processed. It was designed and built to work this way.
I would disable the button with JavaScript once it has been clicked.
UpdatePanel? I will assume you are using MS AJAX, if so I will recommend you download the AJAX toolkit if you have not done so. This toolkit comes with many ready to use controls, and extensions to help you in your AJAX enabled app. For example, there is one extension called "ConfirmButton" that will help you prevent the user from clicking in a button more than once, and it also does it in a very cool and elegant manner.
Another option will be to use JavaScript or better yet, create a custom button control that has a property to be disabled after it is clicked, if you do that, it will be really easy to reuse it in your other applications.
Hope this helps.
In a home-rolled AJAX framework I worked on awhile back, we simply logged the last call in javascript (javascript function call with many parameters) and prevented subsequent calls with identical parameters. It wasn't ideal, but it did the trick in a pinch.
I was having some "Asyc" problems with infragistics control, but after adding ScriptMode="Release" in Scripmanager the problem was resolve.
The link below solved my problem in about half an hour. Just going with a javascript disable (and I tried several different ways...) did not do the trick due to the timing of the updatepanel.
Disabling UpdatePanels While an Asynchronous Postback is in Progress