Dear Hwang, I can view Ejs from new link that you added. However, the window of simulation appeared without [b:69cde6f6eb]Play[/b:69cde6f6eb] function and Photon [b:69cde6f6eb]Energy[/b:69cde6f6eb], [b:69cde6f6eb]Work Function[/b:69cde6f6eb] as well as [b:69cde6f6eb]Light Intensity [/b:69cde6f6eb]did not work either (even it said that [color=blue:69cde6f6eb]File succesfully read:fkhxml/photoelectriceffect.xml[/color:69cde6f6eb]). (I will send the immages to your email address later.) Then I try to get Ejs from old link but an error appeared against. The simulation was not loaded correctly. I really need your help Thank you very much