writable: false means no code can reassign window.Audio to a different value. configurable: false means no code can even call Object.defineProperty again to change those settings. If fermaw’s initialisation code tried to restore the original Audio constructor (a perfectly sensible defensive move) the browser would either fail or throw a TypeError. The hook was permanent for the lifetime of the page.
Shortcut Pre-calculation: For the most commonly used speed profiles, the travel costs (time/distance) for shortcuts between border points within each cluster are pre-calculated and stored. (Each border point effectively has an "entry" and "exit" aspect for directed travel).。业内人士推荐WPS下载最新地址作为进阶阅读
if (res === '') res = '0';，更多细节参见safew官方版本下载
Source: Computational Materials Science, Volume 266