gistfile1.js

function Promise(){
    this.requestIsSuccess = false;
    this.onSuccessCallback = false;
}

Promise.prototype.success = function(callback){
    if(this.requestIsSuccess){
        callback(this.data)
    } else {
        this.onSuccessCallback = callback;    
    }
    
}

Promise.prototype.requestSuccess = function(data){
    if(this.onSuccessCallback){
        this.onSuccessCallback(data);
    } else {
        this.data = data;
        this.requestIsSuccess = true;        
    }
}

function post(url){
    var promise = new Promise()

    $.post(url, data, function(data){
        promise.requestSuccess(data);
    });

    return promise;
}