Get pixel coordinates of HTML/DOM elements using PHP - php

Question

I am working on an web crawler/site analyzer in php. What I need to do is to extract some tags from a HTML file and compute some attributes (such as image size for example). I can easily do this using a DOM parser, but I would also need to find the pixel coordinates and size of a html/DOM tree element (let's say I have a div and I need to know which area it covers and on which coordinate does it start and if). I can define a standard screen resolution, that is not a problem for me, but I need to retrieve the pixel coordinates automatically, by using a server-side php script (or calling some java app from console or something similar, if needed).
From what I understand, I need a headless browser in php and that would simulate/render a webpage, from which I can retrieve the pixel coordinates I need. Would you recommend me a open-source solution for that? Some code snippets would also be useful, so I would not install the solution and then notice it does not provide pixel coordinates.
PS: I see people who answered missed the point of the question, so it means I did not explain well that I need this solution to work COMPLETELY server-side. Say I use a crawler and it feeds html pages to my script. I could launch it from browser, but also from console (like 'php myScript.php').

Answer 1

maybe you can set the coordinates as some kind of metadata inside your tag using javascript
$("element").data("coordinates",""+this.offset.top+","+this.offset.left);
then you have to request with php
$html = file_get_contents($url);
$doc = new DOMDocument();
#$doc->loadHTML($html);
$tags = $doc->getElementsByTagName('element');
foreach ($tags as $tag) {
echo $tag->getAttribute('data'); <-- this will print the coordinates of each tag
}

Answer 2

A Headless browser is an overkill for what you're trying to achieve. Just use cookies to store whatever you want.
So any time you get some piece of information, such as an X,Y coordinate, scroll position, etc. in javascript, simply send it to a PHP script that makes a cookie out of it with some unique string index.
Eventually, you'll have a large array of cookie data that will be directly available to any PHP or javascript file, and you can do anything you'd like with it at that point.
For example, if you wanted to just store stuff in sessions, you could do:
jquery:
// save whatever you want from javascript
// note: probably better to POST, since we're not getting anything really, just showing quick example
$.get('save-attr.php?attr=xy_coord&value=300,550');
PHP:
// this will be the save-attr.php file
session_start();
$_SESSION[$_GET['attr']] = $_GET['value'];
// now any other script can get this value like so:
$coordinates = $_SESSION['xy_coord'];
// where $coordinates would now equal "300,550"
Simple continue this pattern for whatever you need access to in PHP