PHP - Page status checker. Based on a cURL request, this script will check if an element is rendered on the requested URL and if it's not found, fire an e-mail alert.

page_status_checker.php

<?php 
	/* 
		Author: Monteiro, Bruno
		E-mail: brunomonteiro3@gmail.com
	*/

	// Simple cURL settings to retrive all data from the submitted URL

	function page_status_checker( $url ) {
		$user_agent='Mozilla/5.0 (Windows NT 6.1; rv:8.0) Gecko/20100101 Firefox/8.0';

		$options = array(

			CURLOPT_CUSTOMREQUEST  =>"GET",        //set request type post or get
			CURLOPT_POST           =>false,        //set to GET
			CURLOPT_USERAGENT      => $user_agent, //set user agent
			CURLOPT_COOKIEFILE     =>"cookie.txt", //set cookie file
			CURLOPT_COOKIEJAR      =>"cookie.txt", //set cookie jar
			CURLOPT_RETURNTRANSFER => true,     // return web page
			CURLOPT_HEADER         => false,    // don't return headers
			CURLOPT_FOLLOWLOCATION => true,     // follow redirects
			CURLOPT_ENCODING       => "",       // handle all encodings
			CURLOPT_AUTOREFERER    => true,     // set referer on redirect
			CURLOPT_CONNECTTIMEOUT => 120,      // timeout on connect
			CURLOPT_TIMEOUT        => 120,      // timeout on response
			CURLOPT_MAXREDIRS      => 10,       // stop after 10 redirects
		);

		$ch      = curl_init( $url );
		curl_setopt_array( $ch, $options );
		$content = curl_exec( $ch );
		$err     = curl_errno( $ch );
		$errmsg  = curl_error( $ch );
		$header  = curl_getinfo( $ch );
		curl_close( $ch );

		$header['errno']   = $err;
		$header['errmsg']  = $errmsg;
		$header['content'] = $content;
		return $header;
	}

	// Store submitted URL in a variable
	$check_url = $_GET['url']; 

	// Store submitted URL data array in a variable
	$result = page_status_checker($check_url);

	// Only the content is relevant, so this will be stored in a variable
	$content = $result['content'];

	// Checking if the HTML comment is available on the rendered content from the submitted URL
	if (strpos($content, '<!-- Rendering OK -->') == false) :

		// Visual debug - Probably will be removed
		echo "Something is wrong with " . $check_url . "<br />";
		echo "Submitting alert e-mail...";

		// Fire an e-mail alert
		$to      = 'email@domain.com';
		$subject = 'Alert!' . $check_url . ' is down!';
		$message = 'Something is wrong with' . $check_url;
		$headers = 'From: email@domain.com' . "\r\n" .
			'Reply-To: email@domain.com' . "\r\n" .
			'X-Mailer: PHP/' . phpversion();

		mail($to, $subject, $message, $headers);
	endif;
?>