console.log("Hello World!"); let strs = ["/hello/world","hello/world.html","http://www.baidu.com"] strs.map(v => console.log(v," => ",search(v))); function search(v){ let ret = v.match(/\.?\w+$/i); if(ret[0][0] == "."){ ret = v.replace(/\.\w+$/i,"") ret = search(ret); return ret }else{ return ret[0]; } }