Cross-Browser Testing

I heard from a friend, he was mentioning about using “DiffChecker” or “JSONFormatter” for Cross-Browser Testing. How can we use them for Cross Browser Testing?

Diffchecker is a diff tool to compare text differences between two text files.
Enter the contents of two files and click Find Difference.

The JSON Formatter was created to help folks with debugging. As JSON data is often output without line breaks to save space, it can be extremely difficult to actually read and make sense of it. This tool hoped to solve the problem by formatting and beautifying the JSON data so that it is easy to read and debug by human beings.