I thought this would be a trivial feature, but I have lost a fair bit of hair trying to figure it out. I have a jquery mobile web page with a select menu. Users click an item in the drop down list, then later click on a link and navigate to another page. Users then click the back button. The desired result is that the selected item remains selected. Right now, the selection is lost, and it defaults to the first element in the list again.
Things I've tried:
1) Use an asp.net dropdownlist with autopostback. This preserves the selected option, but then I get a page flicker because the entire page is posted back.
2) Wrap above asp.net dropdownlist in an updatepanel. This preserves, doesn't flicker, but it wipes out the jquery mobile styling. Also tried some suggested workarounds with firing a jquery create event, but couldn't get anything working.
3) Write cookies on the select change event in javascript, and read them in the asp page_load event. However, page_load is not called when the back button is clicked, so this had no effect.
4) Tried creating a jquery ajax request to a web page method, but the method must be static and therefore I can't get it to modify the page.
Any other ideas? Is it just me or should this indeed be a problem that's been solved a million times?
As an FYI, I am a newbie at web programming, so please spell it out if you have an answer :) (come from a c++/database background).
Thanks!
Turns out even the date scroller could not survive a back button in some cases. For example if the user navigates to another site, and then uses the back button to come back to my jquery mobile site, all my javascript dom manipulations are lost. The solution is non-trivial. I store everything I need to maintain state of a page using html 5 local storage. On the jqm show page event, I detect if all my global variables have been wiped clean, and if so, reload state from local storage. Works perfectly, but it is quite an implementation task. And of course, if local storage is not supported by underlying browser, it all falls to pieces.
Related
I am completely new to web development. The question I have is rather simple (I guess), but after multiple hours of using google and experimenting I am still without any solution. The problem I have is probably not how to do it, but which keywords to use while searching.
I want to create a simple website. (For testing I use Caddy Server). For my website I use a simple index.html file. On my website I want to have 9 buttons, which will be disabled once clicked. After refreshing the page, every client should also see the changes, so the button-state has to be stored somewhere on the server.
Then there will be another button, which sets the web page to its initial state (all buttons enabled). The purpose of this web page is that 2 persons can click buttons successivley until only one button is left enabled (the web page reloads itself every second on every client). This will be used to select a certain map from a map-pool of 9 maps.
My main problem is, to store the button states, so after refreshing the page the buttons should be still disabled if they were clicked. All clients should see the buttons as diabled once they refresh their pages. Do I have to implement a database for this or store the button states in xml or json? Do I need javascript, jquery, php or ajax for this? I do not want to make it very complicated, so if I need for example a database for this, I will probably just give up.
What I'm asking for: Any point in the right direction on how to implement a simple button that keeps its state after reloading the page would be much appreciated. I found a solution for this using JQuery, but it does not work for me (button does not preserve state after refreshing See here).
Thank you so much for any help!
Your server will need a data store (database) to save the values desired for each button.
Client Side
Set disabled attribute on all relevant buttons in your HTML. On (client-side) page load, fetch the value(s) from your server (database) and depending on what the returned value(s) are, .clearAttribute("disabled") on all buttons accordingly.
Server Side
Have your server set the disabled attribute on the HTML <button> elements based on values in your database prior to serving the HTML to your client(s).
want to have search functionality as on this website
http://www.carwale.com/new/search.aspx#budget=6&budget=8&fuel=2
here whenever the user filters search(checks any checkbox), it updates results accordingly,
that can be understood as an ajax filter.
But at the same time, the query string also reflects for the change,
which helps the user to bookmark the filter search for later reference.
changing it through asp.net/javascript may cause the page to reload..
any hint or suggestions on implementing the same would be really helpful..
This can be done with the help of 3 things together
1) as #Aristos said, checkboxes with Auto Postback enabled
2) Ajax control toolkit Modalpopup, which gets fired automatically on every async postback (http://weblogs.asp.net/ruslan/pages/ajax-update-progress-updateprogress-in-ajax-modal-popup-modalpopupextender.aspx or http://mattberseth.com/blog/2007/07/modalpopup_as_an_ajax_progress.html)
3) History Points (http://msdn.microsoft.com/en-us/library/cc488548.aspx)
This can be done completely without the use of jQuery, if you dont want to use it.
-- For the first part, he have a set of check boxes list with autopostback.
In every post back the list is updated base on the selected check box.
All is simple until now, the cool is that is have a nice interactive interface (made with javascript and jQuery).
-- About the second part, how its change the url so can be bookmark with out reload the page. The trick here is that is place the parameters after the anchor # eg:
/new/search.aspx#budget=2
Using the anchor # the page is not reload and stay as it is. So when some one click on the check boxes, via javascript is also update the url, but only what is after the # so the page stay as is with out fully reload.
Now the parameters after the # can not read on code behind but only via javascript.
So when you have bookmark this page and you go direct to eg /new/search.aspx#budget=2 the javascript reads what is after the # and translate it to commands, check the appropriate checkboxes, and ask for refresh the content. All that can be done only via javascript.
I see that is use the jQuery history plugin as helper with this schema.
http://archive.plugins.jquery.com/project/history
The same trick with parameters after # is done from amazon, when you navigate on catalog, from page to page.
-- One more clever trick that is done is that is open a full page wait, so the user can not interact with the page until the page is ready again. If it not do that, and the user make very fast two clicks on the check boxes, then this can cause a full page post back on updatepanel and this can lose the previous settings.
I am a little confused and making it alot more complicated than this needs to be! Here is what I have...
A view which displays a drop down of US States. When the user chooses a state it loads a list of data from a database and returns the results (populates the View Model) and the View renders the information.
What I wanted to do was have have the dropdown trigger an Ajax event which performs the data load, but also wanted it to depreciate if the user didn't have Javascript enabled. How would I go about rendering the view with AND without javascript / ajax?
Hope that makes sense. Thanks for your help.
You can't re-populate a drop-down without jscript. You can do a page-reload with a new drop-down though, although the logic to determine which to use is javascript unfortunately. (Not to mention triggering the re-load of the page on click)
No Javascript support though? That seems kind of out of date, most people run javascript-enabled browsers these days. As for paranoia freaks with javascript turned off, a <noscript> block to tell them to get over it may be appropriate.
To do this with ajax, read this article about cascade dropdowns by Stephen Walther.
To do this without ajax, you could put your first dropdown in a form with a button visible only when javascript is disabled (hide this with javascript for that) wich gets to some action (in another window, maybe) wich returns the second dropdown populated according to the element selected on the first (on the first window, if you have 2 - you could know this url using a viewstate variable).
i need to implement a back button for my asp.net website.I am able to use the javascript method to acheive my requirement.But using this method sometimes I need to click on the back button multiple number times to go back to the previous page.It may be because we are using jquery tabs in our website.To focus on a particular tab,other than the 1st tab on page load I am using Page.ClientScript.RegisterStartupScript(....).So I am unable to take the user back to the previous page with just one click.
I also tried with asp.net-C# methods mentioned in the following link.
http://www.dotnetcurry.com/ShowArticle.aspx?ID=89
I am able to go back to the previous page, but its state is being lost.Could someone please help me in acheiveing my requirement?
Details:
I have page1.aspx,page2.aspx(which contains jquery tabs view/edit).
In the page1.aspx there are 2 buttons(View,Edit).If I click on view button it takes me to page2.aspx View tab(1st tab) and if I click on the edit button it has to take me to page2.aspx with Edit tab loaded.both View/Edit tabs contain back button.
Also from the View tab I can navigate to the Edit tab,by clicking on another Edit button present in it.
Thanks.
The methods you have covered in your question are essentially what is available to you.
You can either
1. Provide a link that uses javascript to make the client go back a page.
2. Provide a link that posts back to the server that redirects you back a page.
I am not sure why the jquery in your webform as described in your question is causing you to click more that once to go back. If you know that it will always take 2 clicks to go back you could try this method:
javascript: window.history.go(-2)
When you are using the postback/redirect method you will always be using a http GET method to retrieve the page you are returning too. If you want to maintain state you will have to do this manually i.e. save the values when leaving the page somewhere, like session or a temporary database, and when returning to the page, during the page load, check to see if the user has these values saved and pre-populate them.
I've done something similar (with automatic redirections though) and I had to keep track of the number of pages to go back in my ViewState (or Session if you're jumping from page to page):
code-behind
public void Page_Load()
{
Session["pagesToGoBack"] = ((int)Session["pagesToGoBack"])++;
}
mark-up:
<input type="button" value="Back" onclick='javascript:history.go(<%= Session["pagesToGoBack"] %>);' />
Be careful to reset the session variable when needed
Made me feel a bit dirty but it worked :)
I'm writing an asp.net web app. and i've hit a bit of a brick wall.
basically i have 2 pages, the main page with a text box in and a popup that contains a treeview.
My problem is this. when i select a treeview item i want the program to perform some database transactions using asp.net and then pass the value retrieved from the database into a javascript function that passes the data back from the popup page to the parent page. My problem is that i cannot find any way of calling a javascript function from asp.net. I've tried assigning attributes to controls on page load, but this does not work as when the page loads the data has not been retrieved from the database.
Have a look at the ClientScriptManager class. You can register scripts from code-behind that will run when the HTML page loads. Those scripts can call other javascript functions on the page.
There are many tutorials and examples on the Web. Here's one I found that may help but there are many more.
How to use the client script manager
You hit the nail on the head when you said "I've tried assigning attributes to controls on page load, but this does not work as when the page loads the data has not been retrieved from the database." You just need to discover when you're pulling the data from the database, and then assign the values after that. Without looking at your code, there's no way to know for sure, but Page_PreRender is probably a good bet to assign your values...it's probably after you're pulling information from the db...it's pretty much the last place that you can make things happen before the html is generated for the client.
You can invoke a function resided in the Main Page and call that function in the Main Page from the Child Page which is your pop up window.
Please refer to these links for references
http://chiragrdarji.wordpress.com/2007/03/10/call-parent-windows-javascript-function-from-child-window-or-passing-data-from-child-window-to-parent-window-in-javascript/
http://www.webmasterworld.com/forum91/2957.htm
http://hspinfo.wordpress.com/2008/01/12/call-parent-windows-javascript-function-from-child-window/
This one helps with retrieving popups from values using javascript
http://www.eggheadcafe.com/articles/20060117.asp
This one shows how to fire a postback using javascript, and manage it in the codebehind.
http://weblogs.asp.net/mnolton/archive/2003/06/04/8260.aspx
If you put them together, and use Control.ClientID to find the actual "html name" of your asp.net controls, you'll be able to set that up in no time.
Might not be the prettiest way to do it in town, and incidentally make little baby Jesus cry, but anyway, it works.
[edit]Oh. I just saw that it seems I answered the question the other way around, or "how to trigger codebehind from Javascript". I think the method I suggest may help you, if you use it right.
The javascript of the popup should pass the information to the parent window, and the parent window function should call a postback when it receives the information.
The javascript of the popup window should be only registered on a postback with the correct information retrieved, so that when the postback occurs on the popup because of the selection of the right information, the window closes and passes the information to the parent page.
The parent page, triggering postback, does the thingies you need it to, and the app resumes "normally" from there on, doing whatever you need it to, outside of the popup page.