Why is it not rendering, how to fix it?

Question

React

https://jsfiddle.net/c9n6ka85/

Answer 1

You have pasted html script tags into the field where the JS code should be.
You need to insert them into the HTML field, and leave the class code in the JS field (only without the script tag), to support JSX, click on the text "javascript + ..." in the JS field, select Babel + JSX in the Language field.
It will turn out like this https://jsfiddle.net/hLtsu2cm/
UPD: in general, if you click on the cloud in the upper left corner, you will be prompted to create a fiddle based on the template, there you can select React + JSX and not worry about connecting react.