报错信息:
D:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/watir-webdriver-0.6.11/lib/watir-webdriver/elements/element.rb:513:in `assert_exists': unable to locate element, using {:id=>"u", :tag_name=>"input or textarea", :type=>"(any text type)"} (Watir::Exception::UnknownObjectException)
from D:/Ruby21-x64/lib/ruby/gems/2.1.0/gems/watir-webdriver-0.6.11/lib/watir-webdriver/user_editable.rb:11:in `set'
from D:/ruby/test.rb:9:in `<main>'
[Finished in 12.1s with exit code 1]