Websites are malleable: users can run code in the browser to customize them. However, this malleability is typically only accessible to programmers with knowledge of HTML and Javascript. Previously, we developed a tool called Wildcard which empowers end-users to customize websites through a spreadsheet-like table interface without doing traditional programming. However, there is a limit to end-user agency with Wildcard, because programmers need to first create site-specific adapters mapping website data to the table interface. This means that end-users can only customize a website if a programmer has written an adapter for it, and cannot extend or repair existing adapters.

In this paper, we extend Wildcard with a new system for end-user web scraping for customization. It enables end-users to create, extend and repair adapters, by performing concrete demonstrations of how the website user interface maps to a data table. We describe three design principles that guided our system’s development and are applicable to other end-user web scraping and customization systems: (a) users should be able to scrape data and use it in a single, unified environment, (b) users should be able to extend and repair the programs that scrape data via demonstration and (c) users should receive live feedback during their demonstrations.

We have successfully used our system to create, extend and repair adapters by demonstration on a variety of websites and we provide example usage scenarios that showcase each of our design principles. Our ultimate goal is to empower end-users to customize websites in an intuitive and flexible way, making the web more malleable for all of its users.

(We have provided a PDF but it is best viewed in the online version at https://kapaya.github.io/px21/, which includes videos demonstrating the system.)