Trouble getting source code from a webpage

Question

I've written a script in php to get the html content or source code from a webpage but I could not succeed. When I execute my script, it opens the page itself. How can I get the html element or source code?

This is the script:

<?php
include "simple_html_dom.php";
function get_source($url)
{
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_BINARYTRANSFER, 1);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    $htmlContent = curl_exec($ch);
    curl_close($ch);
    $dom = new simple_html_dom();
    $dom->load($htmlContent);
    return $dom;
}
$scraped_page = get_source("https://stackoverflow.com/questions/tagged/web-scraping");
echo $scraped_page;
?>

Currently I'm getting like this:

My expected output is something like:

Btw, echoing $htmlContent also gives me what you can see in image 1.