var city = '48';
var day  = 'tomorrow';
var name = 'lwws1';
var proxy  = 'http://app.drk7.jp/xml2json/';

var lwws1 = {};
lwws1.init = function() {
    var script = document.createElement('script');
    script.charset = 'UTF-8';
    script.src = proxy + 'var=' + this.name + '&url=' + 
                 escape('http://weather.livedoor.com/forecast/webservice/rest/v1?city=' + this.city + '&day=' + this.day);
    document.body.appendChild(script);
}

lwws1.onload = function(data){
    var d = document.getElementById('id_tomorrow');
    d.innerHTML = '<img alt="" src="' + data["image"]["url"] + '"/>'+ 
                  data["telop"];
}
var old = window.onload;
window.onload = (typeof old != 'function') ?
    lwws1.init : function(e) { old(e); return lwws1.init(e); };