Stress Testing: - We need to check the performance of the application.
Testing conducted to evaluate a system or component at or beyond the limits of its specified requirements.
It is used for validating the performance of the application by increasing the client expected users to the maximum level and identify the break point of the application this is called "stress testing".
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Resolution Testing: - Some times developer created only for 1024 resolution, the same page displayed a horizontal scroll bar in 800 x 600 resolutions. No body can like the horizontal scroll appears in the screen. That is reason to test the Resolution testing.
We are performing testing on resolution of the application is called "Resolution testing".
Cross-browser Testing: - This testing some times called compatibility testing. When we develop the pages in IE compatible, the same page is not working in Fairfox or Netscape properly, because most of the scripts are not supporting to other than IE. So that we need to test the cross-browser Testing.
Performing testing on the application in different browsers is called "cross-browser testing" or "compatibility testing"