XMLHttpRequest，使用超过1不会工作，只是第一个。需要使用多个

Why in this code it only loads the first script? the ones next wont load for some reason, i tried different combinations and nothing works, i have tried to change the variable names, the values inside the code, but nothing makes the code work. What should i change to make the script work again and again? like a loop.Why in this code it only loads the first script