Special Field Operation
- How to set a fixed value for a field If you want to set a fixed value for a field, then just ignore the target element, and fill in the fixed value in Default value box.
- How to scrape a field but without saving to output table Some time, we need to scrape a field as a intermediate, for example, extracting an element's URL, and open it for node to process, but no need to dump the URL to output table. So we can uncheck the Dump checkbox. Then NDS will not save the field's value to the output data table.
How to use an element's value as a field name
Take the amazon detail page for example, the product has a specifications table. However, different products may have tiny different attributes. To scrape all such products into one table, we would like use the value in the left column as field's name, and the value in the right column as field's value.
There are severals ways to implement such scraping. For example, we can write css selector, TH:equals("Cable Length") + TD, to locate the right column by the content in the left column. NDS provides a simple way to handle such scenario.
In the detail field, select 'Dynamic Element' as Field Name's source, then locate the left column on the table; now select the right column as field's value element.
In the foregoing screenshot, you find that NDS extract left column's text as field name, and right column as the field's value.
- How to scrape elemeny whose content shown when moving mouse on
There are several scenario that the content of target element is ready when
- moving mouse on another element
- click a link
- scroll the target element into View
NDS supports all these special cases. For each field, there is a Field Pre-Action ( ). Click the icon, you can declare to impose action(s) on the current field element.
- Click : click the current field element
- Scroll to: scroll to the current field element, and simulate moving mouse on it
- Activate Current Tab: activate the current tab
- How to merge fields into one When the current data row is ready to be dumped to data table, you can merge fields. It can be done in recipes' Trigger. more details please refer to Trigger