javascript - 在 ajax 完成之前运行 switch 语句

Question

问题:

有什么方法可以暂停 javascript 直到 ajax 完成执行其成功函数吗？

相关代码:

function validateinput (name, parent, access)
{
    //we assume that the input does not exist
    exists = false;
    //validate with server, expected response is true or false
    $.post("AJAXURL", {action: "category", name: name, parent: parent}, 
    function (data, textStatus, xhr)
    {
        //if returned true, the entry does exist for that parent
        if (data == "true")
        {
            alert("AJAX");
            exists = true;
        }
        else
            exists = false;
    });

    switch (true)
    {
        //If the name field is blank (still displaying hint)
        case (name == 'Subcategory Name' || name == 'Category Name'):
            alert("Please enter a name");
            break;
        //if the name already exists for that parent
/*****/     case (exists == true):
            alert("SWITCH");
            break;
        //if the parent field is displaying hint, assume parent is blank
        case (parent == 'Parent Category'):
            parent = '';
            break;
        //if the usergroup field is blank, assume value of parent
        case (access == 'UserGroup Allowed To View'):
            //if parent is also blank, assume lowest level usergroup access
            if (parent == '')
                access = "UserGroupTicketWorkers";
            else
                    $.post("AJAXURL", {action: "specificcat", name: parent}, 
                function (data, textStatus, xhr)
                {
                    access = data['access'];
                }
                );
            break;

        default:
            return true;
    }
    return false;
}

问题的详细说明:

• 用户点击页面中的链接即可触发此功能。
• 无论用户输入是否有错误，函数都会返回 true 或 false
• 执行此代码时，我会在收到 alert("AJAX"); 之前收到 alert("SWITCH"); (第二种情况的情况当前为正确，我在调试中颠倒了它以弄清楚发生了什么)
• 我对此有一个临时修复，即将第二种情况直接移到默认情况之前，但我的猜测是，速度更快的计算机执行开关比较的速度可能比服务器提供响应的速度更快，因此不是永久解决方案。 (除非它不能那样工作)，并且如果我放入一个计时器来等待预设的时间，如果服务器运行速度比正常慢，则可能会出现相同的问题
• 我知道我没有从 ajax 调用中获取新值，因为与服务器通信花费了时间，所以，我的第一个想法是找到一种方法来暂停该函数，直到 ajax 成功函数完全的。
• 我无法将开关放在 ajax 调用中，因为该函数需要返回一个值。

分辨率

我使用了异步设置，它的效果非常好。只需将我的代码从 $.post() 更改为 $.ajax() 并将其设置为发布

$.ajax(
{
    url: "plugins/actions/edittickets/libs/changetickets.php", 
    type: 'POST',
    data: 
    {
        action: "category", 
        name: name, 
        parent: parent
    }, 
    async: false,
    success: function (data, textStatus, xhr)
    {
        //if returned true, the entry does exist for that parent
        if (data == "true")
            exists = true;
    }
}); 

Answer 1

尝试返回 exists，如下所示。

function validateinput (name, parent, access)
{
    //we assume that the input does not exist
    var exists = false;
    //validate with server, expected response is true or false
    $.post("AJAXURL", {action: "category", name: name, parent: parent}, 
    function (data, textStatus, xhr)
    {
        //if returned true, the entry does exist for that parent
        if (data == "true")
        {
            alert("AJAX");
            exists = true;
        }
        else
            exists = false;

        switch (true)
        {
            //If the name field is blank (still displaying hint)
            case (name == 'Subcategory Name' || name == 'Category Name'):
                alert("Please enter a name");
                break;
            //if the name already exists for that parent
            case (exists == true):
                alert("SWITCH");
                break;
            //if the parent field is displaying hint, assume parent is blank
            case (parent == 'Parent Category'):
                parent = '';
                break;
            //if the usergroup field is blank, assume value of parent
            case (access == 'UserGroup Allowed To View'):
                //if parent is also blank, assume lowest level usergroup access
                if (parent == '')
                    access = "UserGroupTicketWorkers";
                else
                    $.post("AJAXURL", {action: "specificcat", name: parent}, 
                    function (data, textStatus, xhr) {
                        access = data['access'];
                    });
                break;

            default:
                exists = true;
        }
    });
    return exists;
}