function setBaseForAjax(base){
    var oa = $.ajax; //keep a reference to the actual ajax call
    $.ajax = function(){
        var len = arguments.length,
            newArgs = [],
            newUrl = len === 2 && (typeof arguments[0]).toLowerCase() === 'string' ? arguments[0]: null,
            newObj = len === 2 && (typeof arguments[1]).toLowerCase() === 'object' ? arguments[1] : (len === 1 && (typeof arguments[0]).toLowerCase() === 'object' ? arguments[0] : null); 

        if(newUrl){
            newUrl = base + newUrl; 
            newArgs.push(newUrl);  
        }
        if(newObj){
            newObj.url = base + newObj.url; 
            newArgs.push(newObj);    
        }
        oa.apply(window, newArgs); //call the real $.ajax method with the modified params
    }; 
}

setBaseForAjax('/home'); //set the base for every ajax call in the application.