Question

我有以下内容可以在表单上生成状态下拉列表：

$states = array( State ,  Alabama ,  Alaska ,  Arizona ,  Arkansas );
echo "<select name= choose_state >
";
foreach ($states as $key => $state)
{echo "<option value= $key >$state</option>
";}
echo "</select>";

How would I go about making sure a user
1) only selects one of the options in the array
2) doesn t select the default value? ([0]=> string(5) "State")

edit: validate in php, this is for a form collecting user information before posting to a db
I tried using in_array and got stuck trying to exclude the default value

Answer 1

我想你少了一些支票。你永远不应该依赖于发布的内容，并始终进行彻底的检查：

$chosen_state = null;

if (array_key_exists( choose_state , $_POST))
{
  $choose_state = $_POST[ choose_state ];
  if (array_key_exists($choose_state, $states) && $choose_state > 0)
  {
    // Value does actually exist in array and is not item 0.
    $chosen_state = $states[$chose_state]);
  }
}

Answer 2

以下示例假设您将为select提供的密钥重新存储在var$state_key中。。。

试试这个：

$max = sizeof($states) - 1; // this is the number of possible values that you have, minus the default
if($state_key != 0 && $state_key > 0 && $state_key < $max)
{
    // do whatever here, you ve got good data at this point
}

顺便说一句，这也假设您的默认值始终是键#0（数组中的第一个）。

Answer 3

正在验证php中的表单提交：

当您在php中提交表单时，Select输入类型会在post中返回选定的值。所以你可以这样做：

$selectedindex = $_POST["choose_state"]; 

if($selectedindex == 0)
{

   echo "Default item has been selected";

}
else{

   echo "Other than default item has been selected ";
   //you can do further validation here for selected item
   //is in between 0 and 5 if you need to do so

}

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