selenium webdriver处理下拉框

例如：

<select id="ShippingMethod" onchange="updateShipping(options[selectedIndex]);" name="ShippingMethod">

<option value="11.61">UPS Next Day Air Saver ==> $11.61</option>

<option value="10.69">UPS 3 Day Select ==> $10.69</option>

<option value="8.34">UPS Ground ==> $8.34</option>

<option value="9.25">USPS Priority Mail Insured ==> $9.25</option>

<option value="7.45">USPS Priority Mail ==> $7.45</option>

<option value="3.20" selected="">USPS First Class ==> $3.20</option>

</select>

我们要选择“UPS Ground ==> $8.34”

代码为：

select=select=browser.find_element_by_xpath("//select[@id='ShippingMethod']")

select.find_element_by_xpath("//option[@value='8.34']").click()