为什么我在python中使用PhantomJS同时拥有两个不同的用户代理？

下面的代码为一个phantomJS实例设置用户代理，打印它，然后刮取一个网站，再次确定它。结果是不同的。这怎么可能？我还没有能够复制出明显的解决方案

1设置一个用户代理

serviceDefaults=["--ignore-ssl-errors=yes",]
desiredDefaults={
          "phantomjs.page.settings.userAgent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) 
           AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Safari/537.36"}

def create_phantomJS():
    driver = webdriver.PhantomJS("phantomjs.exe", desired_capabilities=desiredDefaults, service_args=serviceDefaults)
    phantom_exc_uri='/session/$sessionId/phantom/execute'
    driver.command_executor._commands['executePhantomScript'] = ('POST', phantom_exc_uri)
    initScript="""             
    this.onInitialized=function() {
        var page=this;
        if (page.navigator == page.settings.userAgent){return};
        page.settings.navigator = page.settings.userAgent;
    }
    """
    driver.execute('executePhantomScript',{'script': initScript, 'args': []})
    agent = driver.execute_script("return navigator.userAgent")
    print "rawUa:", agent
    return driver

2设置驱动程序和打印用户代理

serviceDefaults=["--ignore-ssl-errors=yes",]
desiredDefaults={
          "phantomjs.page.settings.userAgent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) 
           AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Safari/537.36"}

def create_phantomJS():
    driver = webdriver.PhantomJS("phantomjs.exe", desired_capabilities=desiredDefaults, service_args=serviceDefaults)
    phantom_exc_uri='/session/$sessionId/phantom/execute'
    driver.command_executor._commands['executePhantomScript'] = ('POST', phantom_exc_uri)
    initScript="""             
    this.onInitialized=function() {
        var page=this;
        if (page.navigator == page.settings.userAgent){return};
        page.settings.navigator = page.settings.userAgent;
    }
    """
    driver.execute('executePhantomScript',{'script': initScript, 'args': []})
    agent = driver.execute_script("return navigator.userAgent")
    print "rawUa:", agent
    return driver

3抓取网站，确定用户代理并打印

def use_driver(driver, URL):
    website = driver.get(URL) 
    html = WebDriverWait(driver, 1).until(EC.presence_of_element_located((By.ID, "rawUa")))
    return text

4比较结果

driver = create_phantomJS()
text = use_driver(driver, URL)
print text

输出是两个不同的用户代理

---

如何在python中匹配此场景中的用户代理？

改进initScrip可能会奏效

initScript="""
this.onInitialized=function() {
console.log("[INFO] TESTING NAVIGATOR VALUE");
if (navigator.userAgent == this.settings.userAgent){return};
navigator={"User-Agent":this.settings.userAgent};
}.bind(this);
"""

导航器必须设置为新对象。驱动程序创建之后的打印不会给出正确的测试结果，因为处理程序onInitialized将在页面创建之后和URL请求之前调用