using an xpath in selenium python

Question

I used firebug in Firefox to get a xpath for a link that did not have an ID assigned to it. The link is a javascript link with an image as the actual button. I'd like to be able to click this link but it's not working.

The actual xpath is '/html/body/div[2]/div/div/div[3]/div/div/table/tbody/tr[1]/td[2]/form/table/tbody/tr[1]/td/div[1]/div/table/thead/tr[2]/th[1]/a/img'

from selenium import webdriver
from selenium.webdriver.common.keys import Keys
driver = webdriver.Firefox()

URL = 'http://example.com'

driver.set_window_size(1024, 768)
driver.get(url)

link = driver.find_element_by_xpath(//*[@id="//html/body/div[2]/div/div/div[3]/div/div/‌​table/tbody/tr[1]/td[2]/form/table/tbody/tr[1]/td/div[1]/div/table/thead/tr[2]/th‌​[1]/a/img"])
for link in links:
 link.click()

I get the following error: is either invalid or does not result in a WebElement. The following error occurred:\\nInvalidSelectorError: Unable to locate an element with the xpath expression //*[@id=/html/body/div[2]/div/div/div[3]/div/div/table/tbody/tr[1]/td[2]/form/table/tbody/tr[1]/td/div[1]/div/table/thead/tr[2]/th[1]/a/img because of the following error:\\n[Exception... "The expression is not a legal expression." code: "12" nsresult: "0x805b0033 (SyntaxError)" location: "<unknown>"]' ; Stacktrace: is either invalid or does not result in a WebElement. The following error occurred:\\nInvalidSelectorError: Unable to locate an element with the xpath expression //*[@id=/html/body/div[2]/div/div/div[3]/div/div/table/tbody/tr[1]/td[2]/form/table/tbody/tr[1]/td/div[1]/div/table/thead/tr[2]/th[1]/a/img because of the following error:\\n[Exception... "The expression is not a legal expression." code: "12" nsresult: "0x805b0033 (SyntaxError)" location: "<unknown>"]' ; Stacktrace:

<a onclick="if(typeof functionx == 'function'){functionx(document.getElement…,'liststuff','');}return false" href="#">

   <img style="border: 0px;" onmouseover="this.src='/add-hover.gif';" onmouseout="this.src='/add.gif';" alt="Add" src="/icon-add.gif"></img>

</a>

Answer 1

与其拥有元素的绝对路径，不如依赖其父元素和属性：

link = driver.find_element_by_xpath('//a[@onclick and @href = "#" and img/@alt = "Add"]')