Trigger function by pressing F5 (update)

Question

I am making an application in PHP that, through the selection of a data of the combobox related to vessel and a date field, I make a SELECT in the database returning some data that is inserted in a table.

I would like as soon as the user select the vessel (1) and for some case he press the button F5 (update) [2] the system calls a function.

I did a search for this feature in Javascript, but could not find.

To get more visual, follow my screen.

Answer 1

The Javascript event that is called before reloading the page by F5 is the beforeunload. I tested the code below and worked with Jquery 3.3.1. Note: some events like the alert are blocked at this event for security reasons.

window.addEventListener("beforeunload", function(event) {
   $.ajax({
       async: false,
       url: 'teste.php',
       data: { dados: "teste"},
       method: "POST"
   });
   return true;
});