The bias in the user population for a site that teaches web development is going to be huge. The link you provide states:
"W3Schools is a website for people with an interest for web technologies. These people are more interested in using alternative browsers than the average user. The average user tends to the browser that comes preinstalled with their computer, and do not seek out other browser alternatives."
"W3Schools is a website for people with an interest for web technologies. These people are more interested in using alternative browsers than the average user. The average user tends to the browser that comes preinstalled with their computer, and do not seek out other browser alternatives."