1. A computer-implemented method for generating an auto-completion list for a cascading style sheet (CSS) selector, comprising: receiving user input that triggers generation of the auto-completion list; parsing a target document that is associated with the CSS selector; collecting from the parsed target document contextual information associated with the CSS selector; analyzing the contextual information and the user input to determine elements that may be used to complete the CSS selector; creating the auto-completion list with the elements; displaying the auto-completion list; and receiving a selection of one of the elements to add the selected element to the CSS selector.