This is something that might be annoying or irritating for end user. Obviously, It's impossible to prevent end user from closing the/any browser. Just think of this if it becomes possible!!!. That will be a horrible web world where everytime you will be attacked by sites and they will not allow to close your browser until you confirm your shopping cart and do
the payment. LOL:) You need to open
the task manager and might have to kill
the running browser exe processes.Anyways; Jokes apart, but I have one situation where I need to alert/confirm from
the user in any anyway when they try to close
the browser or change
the url. Think of this: You are creating a single page intranet asp.net application where your employee can enter/select their TDS/Investment Declarations and you wish to at-least ALERT/CONFIRM them if they are attempting to:[1] Close
the Browser[2] Close
the Browser Tab[3] Attempt to go some other site by Changing
the urlwithout completing/freezing their declaration.So, Finally requirement is clear. I need to alert/confirm
the user what he is going to do on
above bulleted events. I am going to use window.onbeforeunload event to set
the javascript confirm alert box to appear. <script language="JavaScript" type="text/javascript"> window.onbeforeunload = confirmExit; function confirmExit() { return "You are about to exit
the system before freezing your declaration! If you leave now and never return to freeze your declaration; then they will not go into effect and you may lose tax deduction, Are you sure you want to leave now?"; } </script>See! you are halfway done!. So, every time browser unloads
the page,
above confirm alert causes to appear on front of user like below:By saying here "every time browser unloads
the page"; I mean to say that whenever page loads or postback happens
the browser onbeforeunload event will be executed. So, event a button submit or a link submit which causes page to postback would tend to execute
the browser onbeforeunload event to fire!So, now
the hurdle is how can we prevent
the alert "Not to show when page is being postback" via any button/link submit? Answer is JQuery :)Idea is, you just need to set
the script reference src to jQuery library and Set
the window.onbeforeunload event to null when any input/link causes a page to postback.Below will be
the complete code:<head runat="server"> <title></title> <script src="jquery.min.js" type="text/javascript"></script> <script language="JavaScript" type="text/javascript"> window.onbeforeunload = confirmExit; function confirmExit() { return "You are about to exit
the system before freezing your declaration! If you leave now and never return to freeze your declaration; then they will not go into effect and you may lose tax deduction, Are you sure you want to leave now?"; } $(function() { $("a").click(function() { window.onbeforeunload = null; }); $("input").click(function() { window.onbeforeunload = null; }); }); </script></head><body> <form id="form1" runat="server"> <div></div> </form></body></html>So, By this post I have tried to set
the confirm alert if user try to close
the browser/tab or try leave
the site by changing
the url. I have attached a working example with this post here. I hope someone might find it helpful.
