我用下面的code发送一个请求：

I'm using the following code to send a request:

var ajaxHandler = new XMLHttpRequest();

ajaxHandler.onreadystatechange = function()
{
   if(ajaxHandler.readyState == 4)
   {
      console.log(ajaxHandler.responseText);
   }
}

ajaxHandler.open("POST", "filterCards", true);
ajaxHandler.send("category="+category+"&tag="+tag);

在PHP的一面，我有这样的：

On the PHP side, I have this:

var_dump($_POST);

不过，即使分类和标签的两个变量具有值，控制台记录一个空数组。我在做什么错后？

However, even though both the variables of category and tag have values, the console logs an empty array. What am I doing wrong with the post?

推荐答案

添加 setRequestHeader 您发送调用之前：

ajaxHandler.setRequestHeader("Content-type","application/x-www-form-urlencoded");
ajaxHandler.send("category="+category+"&tag="+tag);

替换：

   if(ajaxHandler.readyState == 4)
   {
      console.log(ajaxHandler.responseText);
   }

与

   if(ajaxHandler.readyState == 4 && ajaxHandler.status==200)
   {
      console.log(ajaxHandler.responseText);
   }

希望这有助于。

Hope this helps.