下面的代码工作得很好。你需要通过id属性到达你的表单元素的输入更改:

var somethingChanged=false;
            $('#managerForm input').change(function() { 
                somethingChanged = true; 
           }); 
            $(window).bind('beforeunload', function(e){
                if(somethingChanged)
                    return "You made some changes and it's not saved?";
                else 
                    e=null; // i.e; if form state change show warning box, else don't show it.
            });
        });

下面的代码工作得很好。你需要通过id属性到达你的表单元素的输入更改:

var somethingChanged=false;
            $('#managerForm input').change(function() { 
                somethingChanged = true; 
           }); 
            $(window).bind('beforeunload', function(e){
                if(somethingChanged)
                    return "You made some changes and it's not saved?";
                else 
                    e=null; // i.e; if form state change show warning box, else don't show it.
            });
        });

简短的回答:

let pageModified = true

window.addEventListener("beforeunload", 
  () => pageModified ? 'Close page without saving data?' : null
)

增加@codecaster的想法 您可以将此添加到表单的每个页面(在我的情况下，我以全局方式使用它，因此只有在表单上才会有此警告)将其函数更改为

if ( formSubmitting || document.getElementsByTagName('form').length == 0) 

同时在表单提交上添加包括登录和取消按钮的链接，这样当人们按下取消或提交表单时，就不会在没有表单的每一页中触发警告…

<a class="btn btn-danger btn-md" href="back/url" onclick="setFormSubmitting()">Cancel</a>

通过jquery

$('#form').data('serialize',$('#form').serialize()); // On load save form current state

$(window).bind('beforeunload', function(e){
    if($('#form').serialize()!=$('#form').data('serialize'))return true;
    else e=null; // i.e; if form state change show warning box, else don't show it.
});

你可以谷歌JQuery表单序列化函数，这将收集所有表单输入并保存在数组中。我想这个解释就足够了:)

您可以使用serialize()通过序列化表单值来创建URL编码的文本字符串，并检查表单在卸载前是否已更改

$(document).ready(function(){
    var form = $('#some-form'),
        original = form.serialize()

    form.submit(function(){
        window.onbeforeunload = null
    })

    window.onbeforeunload = function(){
        if (form.serialize() != original)
            return 'Are you sure you want to leave?'
    }
})

参考这个链接https://coderwall.com/p/gny70a/alert-when-leaving-page-with-unsaved-form 作者:弗拉基米尔·西多伦科