#Detect browser message (WP based sites) This is a function I created for Event Espresso to detect older versions of browsers being used to view the site and displaying a message when out of date (according to our requirements). It uses the `wp_check_browser_version()` function WordPress makes available. I've also added some things to not includ…

show_browser_message.php

<?php
/**
 * This function just checks the incoming browser and will display a message if it's out of date.  We save transients for the user-agents so we don't need to ping the WordPress api on every request.
 *
 * @return string html formatted message for user
 */
function show_browser_message() {
  //let's include the file that will has the wp function we need.
	require_once( ABSPATH . 'wp-admin/includes/dashboard.php' );

	$browser_info = wp_check_browser_version();
	$ie_required = '9.0';
	$msg = '';

	$search_engines_bots = 'Google|Yahoo|msnbot|bingbot';

	if ( preg_match("/$search_engines_bots/", $_SERVER['HTTP_USER_AGENT']) > 0 )
		return; //get out this is most likely a search engine so we don't need to show browser message.

	if ( isset($_SERVER['HTTP_X_GOOG_SOURCE']) )
		return;  //this is supposed to to work for google + (see http://code.google.com/p/google-plus-platform/issues/detail?id=178)

	//first let's handle ie separately from all the others b/c it's the biggest pain
	if ( $browser_info['name'] == 'Internet Explorer' && $browser_info['version'] < $ie_required ) {
		$msg .= 'It appears that you are using Internet Explorer ' . $browser_info['version'] . ' which is <strong>NOT</strong> supported and you may experience difficulty viewing or interacting with our website.  For best results, feel free to use the latest <a href="http://www.microsoft.com/windows/internet-explorer">Internet Explorer</a>, <a href="http://www.firefox.com/">Firefox</a>, or <a href="http://www.google.com/chrome">Google Chrome</a> browser.'; 
	} else if ( $browser_info['name'] == 'Internet Explorer' && ( $browser_info['version'] == $ie_required || ( $browser_info['version'] > $ie_required && $browser_info['version'] < '10.0' ) ) ) {
		$msg .= 'It appears that you are using Internet Explorer ' . $browser_info['version'] . ' which is supported on our website.  However, there have been reports of customers having problems making purchases with this version.  For best results, feel free to use the latest <a href="http://www.microsoft.com/windows/internet-explorer">Internet Explorer</a>, <a href="http://www.firefox.com/">Firefox</a>, or <a href="http://www.google.com/chrome">Google Chrome</a> browser.';
	} else if ( $browser_info['upgrade'] && $browser_info['name'] !== 'Internet Explorer' ) {
		$msg .= 'It appears you are using an older version of ' . $browser_info['name'] . '. More than likely there will be parts of our website that won\'t work as expected for you using this browser.  We suggest upgrading to the latest version <a href="' . $browser_info['update_url'] . '">here</a>.';
	}

	if ( !empty($msg) ) {
		$msg .= ' See <a href="http://eventespresso.com/faqs/supported-web-browsers/">this page</a> regarding supported web browsers for all our products.';
		$msg = '<div id="pue_s2custom-renewal-msg-section" class="pue_s2custom-renewal-msg-section"><p>' . $msg . '</p></div>';
	}
	echo $msg;
}