如何使用php提交html页面的表单

i need to know if is possible to load an html page and submit the form inside this page using php. so something like:

<?php
   $html = fopen("http://www.mysite.com","r");
   //get position of form...
   ...
   //submit it 
?>

is possible? can someone help me? thanks!!!

EDIT:

i have to submit this form

https://annunci.ebay.it/pubblica-annuncio

my problem is that in this page there is an image upload and i don't know how to do that using php( scraping it )

Basically this is what you need to do

1- Get the content of the HTML page using file_get_contents() (bearing in mind the security risks)
2- Parse the HTML using DOMDocument
3- Get the form's attributes, most importantly (ACTION, METHOD) using DOMDocument
4- Get the form's fields' names using DOMDocument
5- Then send to the ACTION url using the method METHOD a request with the data you want replacing the fields using cURL

You can also use curl to POST to any URL, for instance the form's action url.

$ch = curl_init('http://example.com/form_action.php');
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, array('your' => 'data', 'goes' => 'here');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

$response = curl_exec($ch);

This will call the URL http://example.com/form_action.php as if it was called from a form with 'your' set to value 'data' and 'goes' set to value 'here'.

To find out the URL you need to POST, you can inspect source code. When doing that, check the "name" atribute on the <input> tags you want to send.

EDIT: If the POST url and the fields can change, you should check @Adan's answer.

As another option, which would be more clean, you could use the eBay API. It provides methods to add new items, and it probably has already built libraries for php, such as the PHP Accelerator toolkit for eBay.

you can use curl for getting page in php. as mentioned in answer @Lumbendil. For parsing the HTML you can use libraries like

http://simplehtmldom.sourceforge.net/

Or you can use

http://code.google.com/p/phpquery/

I am providing a code that I got from net to get the contents of a page. After that you can use jquery(maybe) to force the submit function.

$url = "URL OF YOUR PAGE"; // I have tested page from same server
$lines = file( $url );
foreach( $lines as $line_num => $line ) {
    $line = htmlspecialchars( $line );
    $line = str_replace( "&lt;", '<span>&lt;', $line );
    $line = str_replace( "&gt;", '&gt;</span>', $line );
    $line = str_replace( "&lt;!–", '<em>&lt;!–', $line );
    $line = str_replace( "–&gt;", '–&gt;</em>', $line );
    echo "<span class=\"linenumber\">Line <strong>$line_num </strong></span> : " . $line . "<br/>
";
}

The above code gave me contents from another page on same server. Now you have to find a way around to check if a form exist and then ; force submit that form.