#获取uui的json文本
def get_preference(d,name):

    d.get('about:config')
    #<button autofocus="" id="warningButton" data-l10n-id="about-config-intro-warning-button">接受风险并继续</button>
    element = find(d,"//button[@id='warningButton']")
    element.click()
    
    #<input type="text" id="about-config-search" data-l10n-id="about-config-search-input1" placeholder="搜索首选项名称">
    element = find(d,"//input[@id='about-config-search']")
    element.send_keys(name)
    element.send_keys(Keys.ENTER)

    element = find(d,"//td[@class='cell-value']/span/span")
    return element.text

#获取扩展的uuid
def getExtendUUID(d,extName):
    #{"doh-rollout@mozilla.org":"98a8be8f-d217-4aa9-aa41-fc8f4fbee980",.....}
    uuids = get_preference(d,"extensions.webextensions.uuids")
    result = json.loads(uuids)
    return result[extName]