Select drop down option using Selenium. Headless chrome. Python

Question

I am attempting to select an option from a drop down menu that expands the records on a page. It works fine when I am not running headless. When I run in headless I get a timeout exception error while the page waits to find the element.

<select name="ctl00$ContentPlaceHolder1$uxTabContracts$uxTabPanelWaintingApproval$uxGridList$ctl05$uxUCGridViewPagingTemplate$uxDropDownListPageSize" onchange="javascript:setTimeout('__doPostBack(\'ctl00$ContentPlaceHolder1$uxTabContracts$uxTabPanelWaintingApproval$uxGridList$ctl05$uxUCGridViewPagingTemplate$uxDropDownListPageSize\',\'\')', 0)" id="ContentPlaceHolder1_uxTabContracts_uxTabPanelWaintingApproval_uxGridList_uxUCGridViewPagingTemplate_uxDropDownListPageSize">
                <option value="5">5</option>
                <option value="10">10</option>
                <option value="20">20</option>
                <option value="30">30</option>
                <option value="40">40</option>
                <option value="50">50</option>
                <option value="100">100</option>
                <option value="250">250</option>
                <option value="500">500</option>
                <option selected="selected" value="1000">1000</option>

            </select>

I have tried using the XPATH, the ID, and Name.

wait.until(EC.presence_of_element_located((By.XPATH,'//*[@id="ContentPlaceHolder1_uxTabContracts_uxTabPanelWaintingApproval_uxGridList_uxUCGridViewPagingTemplate_uxDropDownListPageSize"]'))) # wait for option to expand page
    ExpandRecords = Select(chrome.find_element_by_xpath('//*[@id="ContentPlaceHolder1_uxTabContracts_uxTabPanelWaintingApproval_uxGridList_uxUCGridViewPagingTemplate_uxDropDownListPageSize"]')) # define element to expand page
    ExpandRecords.select_by_value('1000') # select page size option from dropdown

The expected result is to select '1000' records and that the page will expand and move on to the next piece of code which will select the necessary records I need. What happens is nothing. and I get a timeout exception.

line 289, in Import_To_CRM
    wait.until(EC.presence_of_element_located((By.XPATH, '//*[@id="ContentPlaceHolder1_uxTabContracts_uxTabPanelWaintingApproval_uxGridList_uxUCGridViewPagingTemplate_uxDropDownListPageSize"]'))) # wait for option to expand page
selenium.common.exceptions.TimeoutException: Message:

Answer 1

For headless browser you have to set the window size to fire on event.Because headless browser can't recognize where to click without window size.

chrome_options = webdriver.ChromeOptions()
chrome_options.add_argument('--headless')
chrome_options.add_argument('window-size=1920x1080');

If above option doesn't work then check if the website is blocking in headless mode using

print(driver.page_source)