How to detect the visitor browser within WordPress

June 15, 2009 at 9:13 am

To ensure maximum cross-browser compatibility on your blog theme, you have to be able to detect the browser used by the visitor. Sure, you can use conditionnal comments, but WordPress itself can detect client browser. Let’s see how to do.

Simply paste the code below in your functions.php file:

function browser_body_class($classes) {
	global $is_lynx, $is_gecko, $is_IE, $is_opera, $is_NS4, $is_safari, $is_chrome, $is_iphone;

	if($is_lynx) $classes[] = 'lynx';
	elseif($is_gecko) $classes[] = 'gecko';
	elseif($is_opera) $classes[] = 'opera';
	elseif($is_NS4) $classes[] = 'ns4';
	elseif($is_safari) $classes[] = 'safari';
	elseif($is_chrome) $classes[] = 'chrome';
	elseif($is_IE) $classes[] = 'ie';
	else $classes[] = 'unknown';

	if($is_iphone) $classes[] = 'iphone';
	return $classes;

Once you saved the file, the function will automatically add a CSS class to the body tag, as shown in the exemple below:

<body class="home blog logged-in safari">

That’s all. You just have to take your stylesheet, and add some browser-specific styles!

Credits goes to Nathan Rice for this awesome trick!