Browser's error log is one of the most useful tool for understanding why something is not working. It shows error messages and network requests and responses. We can understand whether the browser is sending correct request and receiving correct response. You can open browser's developer tools window using F12 key in most browsers, or if you are using Safari you can open it with CMD+OPTION+C key combination. You can learn how to open developer tools for each browser from this article.
When you open Browser's developer tools window has lots of tabs such as "Elements", "Console", "Network" etc. The ones we need to check are "Console" and "Network" tabs.
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