In order to pass this test you must add an alt attribute to every <img> tag used into your webpage.

An image with an alternate text specified is inserted using the following HTML line:

<img src="image.png" alt="text_to_describe_your_image">

Remember that the point of alt text is to provide the same functional information that a visual user would see. Search engines, users who disabled images in their browsers and other agents who are unable to see the images on your webpage can read the alt attributes assigned to the image since they cannot view it.

Learn more about optimizing images for SEO.

In order to pass this test you must create an account on Google Analytics site and insert into your page a small javascript tracking code.

Example:

<!-- Google Analytics -->
<script>
(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','//www.google-analytics.com/analytics.js','ga');

ga('create', 'UA-XXXX-Y', 'auto');
ga('send', 'pageview');

</script>
<!-- End Google Analytics -->

Note that you have to change the 'UA-XXXX-Y' with the proper id which you'll find in your analytics account.

In order to resolve this problem you are advised to:

• use gzip compression
• move all CSS style rules into a single, external and minified CSS file
• minify all JS files and, if possible, try combining them into a single external JS file
• use CSS layouts

Media queries allow you to style elements for specific devices (smartphones, tablets, desktop computers) by using attributes like width, height, resolution, aspect ratio, orientation or color. By using media queries, presentations can be tailored to a specific range of output devices without changing the content itself.

Example:

<link rel="stylesheet" media="screen and (min-width: 480px) and (max-width: 960px)" 
href="480-960.css" />
 
<!-- OR -->
@media screen and (min-width: 480px) and (max-width: 960px) {
    #header {
        display: none;
    }
}

A @media rule specifies the target media types of a set of statements. In the example above, we are specifying the media type screen. The max-width and min-width features are telling the browser that at any screen size larger than 480px, but smaller than 960px, hide any elements with id="header".