如何设置使用javaScript创建的图像的样式

thanks to Stack Overflow I managed to solve an issue I was having with inconsistent transitions by preloading an image using javaScript. To skip over what is working I won't post all the code. In short, I have an image on my html and a button that when clicked triggers a transition in which another image takes its place with a slide down. The inconsistencies I was getting got solved by creating the img in my javascript (as it gets loaded faster that way). I then apply some classes that perform the transition. Here is the relevant code:thanks to Stack Overflow I managed to solve an