解析URL，From http://bbs.html5cn.org/thread-436-1-25.html

parseURL.js

function parseURL(url) {
  var a =  document.createElement('a');
  //创建一个链接
  a.href = url;
  return {
    source: url,
    protocol: a.protocol.replace(':',''),
    host: a.hostname,
    port: a.port,
    query: a.search,
    params: (function(){
      var ret = {},
      seg = a.search.replace(/^\?/,'').split('&'),
      len = seg.length, i, s;
      for (i=0;i<len;i++) {
        if (!seg[i]) { continue; }
        s = seg[i].split('=');
        ret[s[0]] = s[1];
      }
      return ret;
    })(),
    file: a.pathname.match(/\/([^\/?#]+)$/i) || '',
    hash: a.hash.replace('#',''),
    path: a.pathname.replace(/^([^\/])/,'/$1'),
    relative: a.href.match(/tps?:\/\/[^\/]+(.+)/) || '',
    segments: a.pathname.replace(/^\//,'').split('/')
  };
}