方法1：
  <script>
    var  url = "?aa=1&w=2&cc=3&ss=我要";
    function getUrlParam(url, paramName ){
    var oRegex = new RegExp('[?&]' + paramName + '=([^&]+)', 'i' ) ;
    var oMatch = oRegex.exec( url ) ;     if ( oMatch && oMatch.length > 1 )
    return decodeURIComponent( oMatch[1] ) ;
    else
    return '' ;
   } 
alert(getUrlParam(url,"aa"));
alert(getUrlParam(url,"w"));
alert(getUrlParam(url,"ss"));
</script>
方法2：
    <script>
     var str = "http://localhost/aaa.aspx?aa=1&bb=2&cc=3&dd=哈哈";
  alert(getUrlParam(str,"aa"));
  alert(getUrlParam(str,"dd"));
  function getUrlParam(url,paramName){
     var reg = new RegExp(".*?" + paramName + "=([^&]*)?&.*?$"+"|.*?"+paramName+"=([^&]*)?$|");
  if(reg.exec(url) == url) return '';
  return url.replace(reg,"$1$2");
  }
  </script>