select 选项 XMLHttpRequest 用于语言选择

Question

请帮我解决这个想法：我想要 select 语言并在选择后刷新页面，它应该更改当前页面的语言。 我的目标：从下拉列表中选择后，我通过 document.getElementById('language'); 获取值 and want to send this value to next page, named ajax_lang.php and set in that page the SESSION and after that want to get the Session to refresh the page with Session laguage.

我已经复制了我尝试过的代码。但是失败了。 请帮我解决。 提前致谢。 part 1.php code for session start: part 2: javascript part 3. html code part 4: ajax_lang.php

if(!isset($_SESSION)) 
     { 
         session_start();
                 
     }?>





<div style="margin-top:39px;background: #e9e9e9;margin-left:158px">
                        <select style="width: 40px;height: 40px;border-radius: 50%;width: 40px;
                                border: none;position: absolute;margin-top: 0px;" 
                                name="language" id="language" onchange="loadDoc(this.value)">
                              <option value=""><?php echo $_SESSION['lang'];?></option>
                              <option value="ru">RU</option>
                              <option value="en">EN</option>
                              
                        </select> 
                  </div>



<script>function loadDoc() {
      const xhttp = new XMLHttpRequest();
      xhttp.onreadystatechange = function() {
        if (this.readyState == 4 && this.status == 200) {
          document.getElementById("language").innerHTML =
          this.responseText;
        }
      };
      //xhttp.open("POST", "ajax_lang.php");
      xhttp.open("POST", "ajax_lang.php");
         var select = document.getElementById('language');
         var lang = select.options[select.selectedIndex].value;
         console.log(lang); // en

       xhttp.send({lang:lang});
    }
    //loadDoc();
    </script>



<?php 
if(!isset($_SESSION['lang'])){
session_start();
$_SESSION['lang']=$_POST['lang'];
}


?> ```

Answer 1

XMLHttpRequest.send不采用普通的 object 作为参数，它采用字符串或URLSearchParams object。 请参阅下面的URLSearchParams示例。

xhttp.send(new URLSearchParams({lang:lang}));