Question

注意：选择选项标记
中的未定义索引

当我在浏览器上打开此程序时，SELECT选项（下拉框）中出现错误“undefined index”。帮帮我朋友

<label>Your location<span class="error">*</span>:</label>
    <select name="loca">
      <option label="Select"></option>
      <option <?php if($_POST["loca"] == "Andaman and Nicobar Islands") echo "selected"; ?>>Andaman and Nicobar Islands</option>
      <option <?php if($_POST["loca"] == "Andhra Pradesh") echo "selected"; ?>>Andhra Pradesh</option>
      <option <?php if($_POST["loca"] =="Arunachal Pradesh") echo "selected"; ?>>Arunachal Pradesh</option>
      <option <?php if($_POST["loca"] =="Assam") echo "selected"; ?>>Assam</option>
      <option <?php if($_POST["loca"] == "Bihar") echo "selected"; ?>>Bihar</option>
      <option <?php if($_POST["loca"] == "Chandigarh") echo "selected"; ?>>Chandigarh</option>
      <option <?php if($_POST["loca"] =="Chhattisgarh") echo "selected"; ?>>Chhattisgarh</option>
      <option <?php if($_POST["loca"] =="Dadra and Nagar Haveli") echo "selected"; ?>>Dadra and Nagar Haveli </option>
      <option <?php if($_POST["loca"] =="Daman and Diu") echo "selected"; ?>>Daman and Diu</option>
      <option <?php if($_POST["loca"] =="Goa") echo "selected"; ?>>Goa</option>
      <option <?php if($_POST["loca"] =="Gujarat") echo "selected"; ?>>Gujarat</option>
      <option <?php if($_POST["loca"] =="Haryana") echo "selected"; ?>>Haryana</option>
      <option <?php if($_POST["loca"] =="Himachal Pradesh") echo "selected"; ?>>Himachal Pradesh</option>
      <option <?php if($_POST["loca"] =="Jammu and Kashmir") echo "selected"; ?>>Jammu and Kashmir</option>
      <option <?php if($_POST["loca"] =="Jharkhand") echo "selected"; ?>>Jharkhand</option>
      <option <?php if($_POST["loca"] =="Karnataka") echo "selected"; ?>>Karnataka</option>
      <option <?php if($_POST["loca"] =="Kerala") echo "selected"; ?>>Kerala</option>
      <option <?php if($_POST["loca"] =="Lakshadweep") echo "selected"; ?>>Lakshadweep</option>
      <option <?php if($_POST["loca"] =="Madhya Pradesh") echo "selected"; ?>>Madhya Pradesh</option>
      <option <?php if($_POST["loca"] =="Maharashtra") echo "selected"; ?>>Maharashtra</option>
   </select>
    <span class="error"><?php echo $locationErr?></span> <br />

Answer 1

在这种情况下添加isset检查总是更好

最好以这种方式写下你的条件

if(isset($_POST["loca"]) && $_POST["loca"]  == "Andaman and Nicobar Islands") echo "selected";

Answer 2

因为你的变量$ _POST [“loca”]没有在第一次请求时设置。

做<?php if(isset($_POST["loca"]) && $_POST["loca"] == "...")

此外，您应在每个选项标签上指定一个值属性。

Answer 3

$ _POST [＆＃39; Loca＆＃39;]仅在您提交表单时才存在，如果没有，请按以下方式初始化$ _POST [＆＃39; loca＆＃39;]：$ _POST [＆＃39; loca＆＃39;] =＆＃34;＆＃34 ;;

/* Initialize var */

$_POST["loca"]="";
$locationErr="";

<label>Your location<span class="error">*</span>:</label>
<select name="loca">
// OPTION
</select>

注意：选择选项标签PHP中的未定义索引

3 个答案: