Difference Between vbs and qfl files in QTP

Here is the difference Between vbs and qfl files in QTP

1. vbs is microsoft's vbscript file while qfl is quick test function library file 
2. vbs is executable file. Just double click vbs file in windows system and code will execute. While Qfl is not executable file. 
3. To Use qfl file in qtp, you must associate qfl file from test settings while vbs file can be included with just "executefile" statement.

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