javascript将相对路径转绝对路径示例

function getAbsoluteUrl(url){
    var img = new Image();
    img.src = url;  // 设置相对路径给Image, 此时会发送出请求
    url = img.src;  // 此时相对路径已经变成绝对路径
    img.src = null; // 取消请求
    return url;
}
getAbsoluteUrl("showroom/list");

/*jslint regexp: true, white: true, maxerr: 50, indent: 2 */

function parseURI(url) {
  var m = String(url).replace(/^\s+|\s+$/g, '').match(/^([^:\/?#]+:)?(\/\/(?:[^:@]*(?::[^:@]*)?@)?(([^:\/?#]*)(?::(\d*))?))?([^?#]*)(\?[^#]*)?(#[\s\S]*)?/);
  // authority = '//' + user + ':' + pass '@' + hostname + ':' port
  return (m ? {
    href     : m[0] || '',
    protocol : m[1] || '',
    authority: m[2] || '',
    host     : m[3] || '',
    hostname : m[4] || '',
    port     : m[5] || '',
    pathname : m[6] || '',
    search   : m[7] || '',
    hash     : m[8] || ''
  } : null);
}

function absolutizeURI(base, href) {// RFC 3986

  function removeDotSegments(input) {
    var output = [];
    input.replace(/^(\.\.?(\/|$))+/, '')
         .replace(/\/(\.(\/|$))+/g, '/')
         .replace(/\/\.\.$/, '/../')
         .replace(/\/?[^\/]*/g, function (p) {
      if (p === '/..') {
        output.pop();
      } else {
        output.push(p);
      }
    });
    return output.join('').replace(/^\//, input.charAt(0) === '/' ? '/' : '');
  }

  href = parseURI(href || '');
  base = parseURI(base || '');

  return !href || !base ? null : (href.protocol || base.protocol) +
         (href.protocol || href.authority ? href.authority : base.authority) +
         removeDotSegments(href.protocol || href.authority || href.pathname.charAt(0) === '/' ? href.pathname : (href.pathname ? ((base.authority && !base.pathname ? '/' : '') + base.pathname.slice(0, base.pathname.lastIndexOf('/') + 1) + href.pathname) : base.pathname)) +
         (href.protocol || href.authority || href.pathname ? href.search : (href.search || base.search)) +
         href.hash;
}

//返回绝对路径，jQuery对象实质上是"类数组"结构（类似arguments)，因此使用[0]可以访问到原生态的对象，然后取"href";
console.log($anchor[0]["href"]);
//返回原始路径
console.log($anchor.attr("href"));