php - 如何让表单记住我输入的值

Question

 <form name="search" method="post" >
 Seach for: <input type="text" name="find" /> in
 <Select NAME="field">
 <Option VALUE="category1">category1</option>
 <Option VALUE="category2">category2</option>
 </Select>
 <input type="submit" name="search" value="Search" />
 </form>

<?php
    if(!empty($_POST)){
        $options = array('category1'=> array('1' => 'dog', '2' => 'cat'), 'category2' =>array('1'=>'flower', '2'=>'grass'));
        $input = trim($_POST['find']);
        $category = $_POST['field'];
        $output = $options[$category][$input];
        echo $output;
}
?>

问题:

如果我输入 1 并选择'category2'，它显示:flower，但输入字段变为空，并且选择框返回'category1'，有什么方法可以让输入框和选择框保持我放在那里的值，在我的例子中，在我点击提交按钮后，“1”仍然在输入字段中，“类别 2”显示在选择框中。

Answer 1

使用 value="<?php if(isset($_POST[])) echo $_POST[]; ?>"

<form name="search" method="post" >
 Seach for: <input type="text" name="find" value="<?php echo (isset($_POST['find']) ? $_POST['find'] : ''); ?>" /> in
 <Select NAME="field">
 <Option VALUE="category1" <?php echo (isset($_POST['field']) && $_POST['field'] === 'category1') ? 'selected="selected"': ''; ?>>category1</option>
 <Option VALUE="category2" <?php echo (isset($_POST['field']) && $_POST['field'] === 'category2') ? 'selected="selected"': ''; ?>>category2</option>
 </Select>
 <input type="submit" name="search" value="Search" />
 </form>