Javascript setTimeout, Loops and Closure
问题 The following code has me confused. My goal is to fade an HTML element from one opacity level to another, over a period of time. Below is my dimScreen() method, used to create a darkened overlay and fade it in. var overlay; function dimScreen() { if(!overlay) { overlay = document.createElement('div'); overlay.setAttribute('id', 'overlay'); overlay.style.width = '100%'; overlay.style.height = '100%'; overlay.style.zindex = '1000'; overlay.style.background = '#000013'; overlay.style.position =