使用JQuery POST的Javascript函数总是返回未定义的 [英] Javascript Function With JQuery POST Always Returns undefined

问题描述

我不知道这里发生了什么，希望有人能帮上忙，我肯定这件事很容易发生，我只是想念。

我在JavaScript中有一个函数，里面有一个JQuery文章。我想返回只是文本的帖子的结果并将其放入一个变量中。这个数字是从Post正确回来的，但是当我把它放在变量中时，变量就会显示undefined。任何想法？

  var total = GetTotalSize（）; 
 alert（total）; 
 
函数GetTotalSize（）{
 var i =; 
 $ .post（Handlers / GetTotal.ashx，{id：$（＃hID）。val（）}，function（data）{
i = data.toString（）; 
返回i; 
}）; 
 
  

解决方案

您无法做到像那样。请记住，AJAX中的A表示异步。在 GetTotalSize（）执行并返回后，您提供给 $。post（）的回调函数将很好地执行。 p>

您需要重构代码以适应此情况。我不能确定我的建议，因为我不知道代码的其余部分是什么样子，但这是一种可能性。

 <$ c $（$ Handler / GetTotal.ashx），{id：$（＃hID）。val（）}，function（data）
 {
 doSomethingWithTotalSize（data.toString（ ））; 
}）; 
 
函数doSomethingWithTotalSize（totalSize）
 {
 //无论
} 
  

I have no idea what's going on here and was hoping someone could help, I'm sure it's something easy going on that I'm just missing.

I have a function in javascript that has a JQuery post inside of it. I would like to return the results of the post which is just text and put it in a variable. The number is coming back correctly from the Post but when I put it in the variable, the variable says "undefined". Any ideas?

var total = GetTotalSize();
alert(total);

function GetTotalSize(){
    var i = "";
    $.post("Handlers/GetTotal.ashx", {id : $("#hID").val()}, function(data){
        i = data.toString();
        return i;
    });
}

解决方案

You can't do it like that. Remember, the "A" in AJAX means "Asynchronous". The callback function you provide to $.post() will execute well after GetTotalSize() executes and returns.

You'll need to restructure your code to accommodate this. I can't be specific in my recommendation because I don't know what the rest of your code looks like, but here's a possibility.

$.post("Handlers/GetTotal.ashx", {id : $("#hID").val()}, function(data)
{
  doSomethingWithTotalSize( data.toString() );
});

function doSomethingWithTotalSize( totalSize )
{
  // whatever
}

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