What is 'Cross Browser Testing' and why do we need it?

'Cross Browser testing' is a type of functional test to check that your application works as expected in different browsers.
Below are some of the main reasons to perform Cross Browser Testing

• Font size mismatch in different browsers.
• JavaScript implementation can be different.
• Some browser still not supporting HTML5.
• Page alignment  and div size issue.
• Image orientation.
• Compatibility issues with OS. 

To execute the Test-cases with different browsers in the same machine at the same time we can integrate frameworks like Junit,TestNG with Selenium Web-driver.