How do I open a form on page exit

I'm now dealing with a client request to 开发者_StackOverflow社区open a form when the user leave the page. Can that be done?

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I think you are looking for

onbeforeunload event

An event that fires before the unload event when the page is unloaded.

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It seems to be impossible to create my own form and override onbeforeunload or anything else. I guess blocking it is the right thing though..

What we did is to pop a form and use the regular onbeforeunload. if the user wants to go - he will. But if he stays - he will get the questionnaire.

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You can see the issue here too: onbeforeunload confirmation screen customization