Why I like W3schools.com:
I am a developer, for me it is very necessary to keep learning new technologies, W3shools.com helps me lot because it provides you easy way to learn, it has simple solutions of problem, not complicated, you will understand easily what it is trying to explain you, you can code also at same place, so it makes easy to learn the concept. W3shools have almost every technologies tutorial, just go through the site and learn whatever you want .
It helps me lot whenever I stuck while coding or working on any project, so I take help from W3schools, many time I have got the solutions, and completed the task.
I will recommend W3shools.com for both type of developers beginner and experienced.
My Recommendations:
If you are beginner try to learn step by step on W3shools.com, first go throw the simple solutions or basics, other wise you will get frustrated, and also keep trying to code simultaneously .
Limitations:
You must have good internet connection, if you learning and coding both.