Checkbox checked in Javascript

Hello,
I spent a day in order to be able to retrieve the value of a checkbox during the validation of the form.

I have a javascript script :
jQuery (document) .on (‘click’, ‘.wpcf7-submit’, function (e)”

I can retrieve data from textbox, however I cannot tell if a checkbox is checked.

In the form I wrote it like this: [urgent checkbox id: urgent “URGENT”]

I tried :
if (document.getElementById (“urgent”) == true) {
urgent = “& urgent = URGENT”;
}

It returns “undefined”.

When I inspect the checkbox in HTML I see this :
<input type = “checkbox” name = “urgent[]” value = “URGENT”>

If you have the solution it would help me a lot …
Thank you ! 🙂