PHP：获取带有Tag Name的元素索引

Question

I'm trying to get the index of an HTML element and pass this to a PHP variable to eventually upload to a database.

<form method="post" action="insert.php" enctype="multipart/form-data">
    ....
    <div><textarea name="paragraph[]"></textarea></div> //index 0
    <div><textarea name="paragraph[]"></textarea></div> //index 1
    <div><textarea name="paragraph[]"></textarea></div> //index 2
    ....
</form>

if(isset($_POST['paragraph'])) {

    foreach ( $_POST['paragraph'] as $paragraph){

    //get index of container div for this paragraph and store it in a variable

    }
}

Looking at this Stack Overflow answer, I'm guessing I should do something like:

$divs = $dom->getElementsByTagName('div');

However, instead of getting all the <div> elements and storing them in an array, is there any way I can get the current <div> element from within the foreach loop and store its index in a variable?

Some clarification: The form is dynamic. So it could look like this, too:

<form>
    <div><textarea name="paragraph[]"></textarea></div> //index 0
    <div><textarea name="something_else"></textarea></div> index 1
    <div><textarea name="paragraph[]"></textarea></div> //index 2
    <div><textarea name="paragraph[]"></textarea></div> //index 3
</form>

Answer 1

You could use a base array to hold all your items such as the below HTML:

<div><textarea name="items[][paragraph]"></textarea></div> //index 0
<div><textarea name="items[][something_else]"></textarea></div> index 1
<div><textarea name="items[][paragraph]"></textarea></div> //index 2
<div><textarea name="items[][paragraph]"></textarea></div> //index 3

Then when you access $_POST['items'] you will have them listed with their indexes:

array (size=1)
  'items' => 
    array (size=4)
      0 => 
        array (size=1)
          'paragraph' => string 'test' (length=4)
      1 => 
        array (size=1)
          'something_else' => string 'test 2' (length=6)
      2 => 
        array (size=1)
          'paragraph' => string 'test 3' (length=6)
      3 => 
        array (size=1)
          'paragraph' => string 'test 4' (length=6)

You can get all the information held in this array easily using the below loop:

foreach($_POST['items'] as $index => $item) {
  echo "Index is: " . $index;
  echo "Key is: " . key($item);
  echo "Value is: " . $item[key($item)];
}

Which will print:

Index is: 0
Key is: paragraph
Value is: test

Index is: 1
Key is: something_else
Value is: test 2

etc.

If you want to get all values for paragraph in one easy swoop you can use array_column to access these, for example the below:

array_column($_POST['items'], 'paragraph');

Will print:

array (size=3)
  0 => string 'test' (length=4)
  1 => string 'test 3' (length=6)
  2 => string 'test 4' (length=6)