Alert for unsaved data on page

[khushbu shah]

In my website we have left panel having different links, our requirement when user clicks on any link and enter any detail on page without save/submit, and then he moves to next link on left panel an alert should be generated to user before the page load for new link happens. In that way an alert for unsaved data can be shown.

Note:- technology/languaage used should be:- VS 2005 asp.net 2.0 using C#, javascript

Thanks in Advance

[tlhintoq]

Sounds like a good requirement. But if you are putting this out for bids, you should post it under Jobs.

This forum is used when people have questions about the code they've written but have run up against problems or errors and need help figuring out the source of the problem.

My compliments on how well you have described what your goals are and your intended plan of action to get there. Not everyone does that as well.
But... What is your question for the volunteers here?
Please visit the Posting Guidelines for tips on how to ask questions to get the best help.

[Frinavale]

Well, since you're using JavaScript already in your solution you are probably aware that this solution will require JavaScript.

You're going to have to write a function that will keep track of any changes that happen to your controls.

You are going to have to set every control on your page to call this when a change occurs....so for every TextBox, set it to call the function that tracks changes during the onkeydown event...for every DropDownList, set it to call the function during the onchange event......etc etc.

Some controls (like calendars) will postback to the server when they are changed...so the server needs to be able to be able to indicate that a change has been made as well. Therefore, you'll probably have to store the boolean value that indicates whether or not changes have been made in a HiddenField so that it is available in both the server and client side code.

You can use the onbeforeunload JavaScript event to let the user cancel leaving your page.

So, the onbeforeunload event will have to call a function that retrieves the boolean value that's being used to track changes.

The onbeforeunload event happens every time the page is about to unload. This means that it happens any time a full page postback occurs.

Therefore all of your buttons, links, and anything else will have to indicate that the page should be unloaded without prompting the user.

So you need another function that registers any control that posts back to the server.....

So really, the method that handles the onbeforeunload event will have to check if any changes have been made, and check if any of your controls caused the page to unload before deciding whether or not to prompt the user.


Happy coding

-Frinny