$.url() - A simple, lightweight url parser for jQuery(github.com)

    http://www.domain.com/path/index.html?query1=test&silly=willy#test=hash&chucky=cheese
    
    $.url('?');         // query1=test&silly=willy
    $.url('?silly');    // willy
    $.url('?poo');      // (an empty string)
    $.url('#');         // test=hash&chucky=cheese
    $.url('#chucky');   // cheese
    $.url('#poo');      // (an empty string)

    else if($.isNumeric(arg)

    var file = $('a#interesting').url('file')

    var file = url($('a#interesting'), 'file');