JavaScript將相對位址轉換為絕對位址

在看LABjs原始碼時，發現裡面有個將相對位址轉為絕對位址的函數，將其拿出紀錄如下：

function canonical_uri(src, base_path){var root_page = /^[^?#]*\//.exec(location.href)[0],root_domain = /^\w+\:\/\/\/?[^\/]+/.exec(root_page)[0],absolute_regex = /^\w+\:\/\//;// is `src` is protocol-relative (begins with // or ///), prepend protocolif (/^\/\/\/?/.test(src)){src = location.protocol + src;}// is `src` page-relative? (not an absolute URL, and not a domain-relative path, beginning with /)else if (!absolute_regex.test(src) && src.charAt(0) != "/"){// prepend `base_path`, if anysrc = (base_path || "") + src;}// make sure to return `src` as absolutereturn absolute_regex.test(src) ? src : ((src.charAt(0) == "/" ? root_domain : root_page) + src);}

如當前頁面地址為：http://www.inspurstb.com/hzt/index.html

則canonical_uri("scy.js")返回http://www.inspurstb.com/hzt/scy.js