PHP：如何检索具有相同名称的多个表单输入的值，？

Question

I have a checkbox, and next to each checkbox I have a select option. I have multiple of these, and I want to retrieve the value of the select only if the checkbox is checked for it.

Here is the code:

<form method="POST">
<fieldset>
    <input type="checkbox" name="check1[]">
    <select name="select1[]">
        <option value="1">One</option>
        <option value="2">Two</option>
        <option value="3">Three</option>
    </select

<fieldset>
    <input type="checkbox" name="check1[]">
    <select name="select1[]">
        <option value="1">One</option>
        <option value="2">Two</option>
        <option value="3">Three</option>
    </select>
</fieldset>
<input type="submit" name="update" value="go">
</form>

Here is my PHP code:

if(isset($_POST['update'])){
    for($i = 0; $i < sizeof($_POST['check1']); $i++){
        if(isset($_POST['check1'][$i])){
            echo $_POST['select1'][$i];
        }
    }
}

This does not work, if the first checkbox is unchecked then the for loop returns the value of the second select option. Otherwise it works fine. How can i fix this?

Here is the array:

[check1] => Array
    (
        [0] => on
        [1] => on
    )

[select1] => Array
    (
        [0] => 1
        [1] => 3
    )

Answer 1

We get only checked check box on server that was your for loop is false over there.

In this code i have add value to each check box to identify select box.

eq: if check1[0] == 0 then we get select1[0]

if check1[1] == 1 then we get select1[1]

Sorry for my english.

Html code

<form action='' method="post">
    <fieldset>
        <input type="checkbox" name="check1[]" value='0'>
        <select name="select1[]">
            <option value="1">One</option>
            <option value="2">Two</option>
            <option value="3">Three</option>
        </select>
    </fieldset>
    <fieldset>
        <input type="checkbox" name="check1[]" value='1'>
        <select name="select1[]">
            <option value="4">One</option>
            <option value="5">Two</option>
            <option value="6">Three</option>
        </select>
    </fieldset>
    <input type="submit" name="update" value="go">
</form>

PHP code:

if(isset($_POST['check1'])){
    for($i=0;$i<count($_POST['check1']);$i++){
        if($_POST['check1'][$i] >= 0){
            echo $_POST['select1'][$_POST['check1'][$i]];
        }
    }
}