jQuery beforeunload不显示消息 [英] jquery beforeunload does not display message

问题描述

用于此目的的jsfiddle位于 http://jsfiddle.net/whDm6/18/

The jsfiddle for this is at http://jsfiddle.net/whDm6/18/

如果在以下代码中取消注释警报，请更改表单值并刷新页面，它将显示警报.所以我知道代码可以执行到这一点.但是，如果我将警报保留为注释状态，它不会像我期望的那样显示beforeunload框.

If I uncomment the Alert in the following code, change a form value, and refresh the page, it displays an alert. So I know the code is executing up to that point. But if I leave the Alert commented out it does not display the beforeunload box like I expect it to.

我尝试过使用bind和基本的window.onbeforeunload = function(){}，但未将其与Jquery绑定，但没有一个起作用.

I have tried using bind and also using a basic window.onbeforeunload = function() {} without binding it with Jquery but none of those worked.

使用Jquery 1.8.2

Using Jquery 1.8.2

var currentUlValues = {};
currentUlValues['input1'] = "red";
currentUlValues['input2'] = "blue";
needToConfirm = true;

$(window).on('beforeunload', function(){
    if (needToConfirm) {
        $.each(currentUlValues, function(key, value) {
            var elem = $("#"+key).val();
            if (typeof elem !== 'undefined') {
                if (elem != currentUlValues[key]) {
                    //alert(elem + " - " + currentUlValues[key]);
                    return 'Are you sure you want to leave?';
                }
            }
        });
    }
});

HTML表单

<form>
    <input id="input1" name="input1" type="text" value="red" />
    <input id="input2" name="input2" type="text" value="blue" />
</form>

推荐答案

您是从.each的回调函数返回的，该回调函数的作用域不正确，您应该在其外部返回字符串.

You are return form the callback function of .each, which is in wrong scope, you should return the string outside it.

工作示例:

$(window).on('beforeunload', function(){
    var is_return = false;
    if (needToConfirm) {
        $.each(currentUlValues, function(key, value) {
            var elem = $("#"+key).val();
            if (typeof elem !== 'undefined') {
                if (elem != currentUlValues[key]) {
                    is_return = true;
                    // here return false is to stop the iterate
                    return false;
                }
            }
        });
        if (is_return) {
            return 'Are you sure you want to leave?';
        }
    }
});

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