How to call window.unload

Question

I am using web socket connection for communication. But when user refresh page, I want to close this web socket connection. I also using window.onbeforeunload event to show confirmation box to user with customized text. If user selects 'do not reload' option then no action (which is working fine) But I want to close web socket connection if user selects reload option. I don't know how to achieve this. I tried to call window.unload and tried to close web socket connection but its not working. My code is as follows.

window.onbeforeunload = function(e) {
     return "you are closing this web page';
};

           
window.unload = function(e) {
     webSockect.closeConnection();
};

Please advise how to achieve this.

Answer 1

Window events are prefixed with on.

Try to use window.onunload = ... or even better

window.addEventListener('unload', ...).

When using addEventListener you specify the event name without on prefix.

Read more: WindowEventHandlers.onunload

Answer 2

First of all, there is a syntax error in the code above, you have written:

window.onbeforeunload = function(e) {
     return "you are closing this web page';
};

So, type of quotes there should be either single or double, same at start and end of the string.

It is supposed to be, and it will work:

window.onbeforeunload = function(e) {
    return "you are closing this web page";
};

====

Back to the point. All you can do with unload prompt is to change the Message. Anything otherwise doesn't work like:

• Changing the action on Buttons on the prompt
• Changing the Button text of the prompt
• Changing the UI of the box

Q. even you write something before the return if the function, that will be ignored by the browser.

Answer 3

You can in fact run a method on close if you assign the method to a variable and then return the variable.

function unloadWebSocket()
{
    webSockect.closeConnection();
}

window.onbeforeunload = function(e) 
{
    var x = unloadWebSocket();
    return x;
};

While I have no experience with websockets, I know this works with synchronous ajax requests.