As a matter of fact that I want to change my fundamental class inheritance to get a better performance. So I do test on my new and old class. First I test on the Firefox:

The 1st number is the milliseconds of loading all the *.js;
The 2nd number is the milliseconds of performing some UI layout actions;
The 3rd number is the milliseconds of performing the all the actions after the *.js is loaded (including the UI layout actions)

Firefox: Class#old
651
1392
3144

Firefox: Class#new
631
911
1673

Then I made tests on IE6, and got the following data:
As refresh action was performed, the IE6 will increase the milliseconds. So I did 2 refreshes on new and old class, and got the following data:
IE: Class#old *1
491
271
681
IE: Class#old *2
611
361
891
IE: Class#old *3
711
481
1141

IE: Class#new *1
511
120
350
IE: Class#new *2
531
160
391
IE: Class#new *3
581
180
480
It seems that IE has a bug of Memory Leak. But its perform was much better than the Firefox. It only took about 1/3 or 1/5 of the time that Firefox was doing the job. It's great, I think. It's the work of year 2001 for IE6, while the Firefox I used is the work of 2005.

By the data, I can tell that loading the *.js can be considered as the same and my new class inheritance will decrease the time to about 50% of the old class inheritance.

No matter how much I love the Firefox/Mozilla, I must admit that IE is still the unbelievable browser in the world.