js判断访问媒体介质

<script type="text/javascript">
	var userAgent = navigator.userAgent.toLowerCase(),
	userTerminal = userAgent.match( /ipad/i ) ||
	userAgent.match( /iphone os/i ) ||
	userAgent.match( /midp/i ) ||
	userAgent.match( /ucweb/i ) ||
	userAgent.match( /android/i );
	if( userTerminal == 'ipad' )
	{
	document.write( '<meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=0">' );
	document.write( '<meta name="apple-mobile-web-app-capable" content="yes">' );
	document.write( '<meta name="apple-mobile-web-app-status-bar-style" content="black">');
	}
	else if( userTerminal == 'iphone os' )
	{
	document.write( '<meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=0">' );
	document.write( '<meta name="apple-mobile-web-app-capable" content="yes">' );
	document.write( '<meta name="apple-mobile-web-app-status-bar-style" content="black">' );
	}
	else if( userTerminal == 'midp' )
	{
	document.write( '<meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=0">' );
	document.write( '<meta name="apple-mobile-web-app-capable" content="yes">' );
	document.write( '<meta name="apple-mobile-web-app-status-bar-style" content="black">' );
	}
	else if( userTerminal == 'android' )
	{
	document.write( '<meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=0">' );
	};
	</script>