php - 为什么 $_POST 从 ajax 请求中一无所获？

Question

var httpRequest = new XMLHttpRequest();
httpRequest.onreadystatechange = action;
httpRequest.open('POST','/fetch_product_list.php','true');
httpRequest.send("var=5");

但在fetch_product_list.php， $_POST['var'] 什么都没有，我该如何解决？

Answer 1

您没有为请求正文包含内容类型。

httpRequest.setRequestHeader("Content-type", "application/x-www-form-urlencoded");

Answer 2

添加行：httpRequest.setRequestHeader("Content-type", "application/x-www-form-urlencoded");因此代码如下所示：

var httpRequest = new XMLHttpRequest();
httpRequest.onreadystatechange = action;
httpRequest.open('POST','/fetch_product_list.php','true');
httpRequest.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
httpRequest.send("var=5");

并在 php 中使用：$_POST['var'].