It is common that a data field may appear at different places on different pages. Therefore, it helps to have a backup XPath in case the primary XPath fails to locate the page element so that when Octoparse cannot find the target data field using the primary XPath, it will go on to use the alternative XPath to match the desired data field. A backup XPath is also known as an alternative XPath in Octoparse.
STEP 1: Click on the ... More icon from your target data field and select Customize XPath
STEP 2: Tick the option for Try alternative XPath and input the alternative XPath
Note: relative XPath and backup XPath cannot be applied at the same time, meaning if relative XPath is used to locate the data field, then the backup XPath will be disabled.