1. An electronic device comprising: one or more computer-readable storage media configured to store instructions; and one or more processors configured to execute the instructions to cause the electronic device to: obtain and display a first sample document; receive a first input indicating selection of one or more objects within the first sample document; determine a first set of one or more characteristics shared by the selected objects; identify, within one or more target documents, one or more target objects characterized by the first set of one or more characteristics; store object data associated with the target objects; obtain and display a second sample document; receive a second input indicating selection of one or more objects within the second sample document; and determine a second set of one or more characteristics shared by objects selected in the first and second sample documents, wherein the first and second sample documents are HTML documents, wherein the one or more objects within the first and second sample documents are HTML elements, and wherein the determination of the second set of characteristics comprises a determination of commonalities among hierarchical positions of the HTML elements within the HTML documents.