Use Dojo to Replace PrototypeJS codes

1.Old PrototypeJS Script:

var loc = document.location.pathname;
var tail = "webengine/generated/Init"
loc = loc.substr(0,loc.indexOf(tail));
var url = loc.concat("protect/RouterServlet?NAV_MENU=TRUE&GREEN_NAV=TRUE");
				
new Ajax.Request(url,{method:'get', onSuccess:function(request){
var elemAjxResp = request.responseText;
document.getElementById('com-navigation').innerHTML = elemAjxResp;;
}});

require(["dojo/_base/xhr", "dojo/dom", "dojo/domReady!"],
    function(xhr, dom) {        
        xhr.get({            
            url: url,            
            load: function(newContent) {
                dom.byId("com-navigation").innerHTML = newContent;
            },            
            error: function() {
			
            }
        });         
});