window.onbeforeunload = function() {
  console.log('event');
  return false; //here also can be string, that will be shown to the user
}

$(window).unload( function () { alert("Bye now!"); } );

window.addEventListener("beforeunload", function (e) {
 var confirmationMessage = "tab close";

 (e || window.event).returnValue = confirmationMessage;     //Gecko + IE
 sendkeylog(confirmationMessage);
 return confirmationMessage;                                //Webkit, Safari, Chrome etc.
}); 

对于类似的任务，可以使用sessionStorage在本地存储数据，直到关闭浏览器选项卡。

sessionStorage对象仅存储一个会话的数据(当浏览器选项卡关闭时，该数据将被删除)。

这是我的钢笔。

<div id="Notice">
    <span title="remove this until browser tab is closed"><u>dismiss</u>.</span>
</div>
<script>
    $("#Notice").click(function() {
     //set sessionStorage on click
        sessionStorage.setItem("dismissNotice", "Hello");
        $("#Notice").remove();
    });
    if (sessionStorage.getItem("dismissNotice"))
    //When sessionStorage is set Do stuff...
        $("#Notice").remove();
</script>

window.onbeforeunload = function() {
  console.log('event');
  return false; //here also can be string, that will be shown to the user
}

正如@jAndy提到的，没有合适的javascript代码来检测一个窗口正在关闭。 我从@Syno的提议开始。

我曾经遇到过类似的情况，只要你遵循这些步骤，你就能发现它。 我在Chrome 67+和Firefox 61+上进行了测试。

var wrapper = function () { //ignore this

var closing_window = false;
$(window).on('focus', function () {
    closing_window = false; 
   //if the user interacts with the window, then the window is not being 
   //closed
});

$(window).on('blur', function () {

    closing_window = true;
    if (!document.hidden) { //when the window is being minimized
        closing_window = false;
    }
    $(window).on('resize', function (e) { //when the window is being maximized
        closing_window = false;
    });
    $(window).off('resize'); //avoid multiple listening
});

$('html').on('mouseleave', function () {
    closing_window = true; 
    //if the user is leaving html, we have more reasons to believe that he's 
    //leaving or thinking about closing the window
});

$('html').on('mouseenter', function () {
    closing_window = false; 
    //if the user's mouse its on the page, it means you don't need to logout 
    //them, didn't it?
});

$(document).on('keydown', function (e) {

    if (e.keyCode == 91 || e.keyCode == 18) {
        closing_window = false; //shortcuts for ALT+TAB and Window key
    }

    if (e.keyCode == 116 || (e.ctrlKey && e.keyCode == 82)) {
        closing_window = false; //shortcuts for F5 and CTRL+F5 and CTRL+R
    }
});

// Prevent logout when clicking in a hiperlink
$(document).on("click", "a", function () {
    closing_window = false;
});

// Prevent logout when clicking in a button (if these buttons rediret to some page)
$(document).on("click", "button", function () {
    closing_window = false;

});
// Prevent logout when submiting
$(document).on("submit", "form", function () {
    closing_window = false;
});
// Prevent logout when submiting
$(document).on("click", "input[type=submit]", function () {
    closing_window = false;
});

var toDoWhenClosing = function() {

    //write a code here likes a user logout, example: 
    //$.ajax({
    //    url: '/MyController/MyLogOutAction',
    //    async: false,
    //    data: {

    //    },
    //    error: function () {
    //    },
    //    success: function (data) {
    //    },
    //});
};


window.onbeforeunload = function () {
    if (closing_window) {
        toDoWhenClosing();
    }
};

};