The present invention extends to methods, systems, and computer program products for mapping breakpoints between Web based documents. Embodiments of the invention facilitate extracting corresponding client script blocks from different Web based documents to disassociate the client script blocks with their relative locations within the Web based documents. From the extracted client side script blocks, a position for mapping a breakpoint from one client side script block another client side script block can be determined. The breakpoint is then copied from the one client script block and inserted into the determined position in the other client script block. The client script blocks can then be re-associated with their relative locations in the Web based documents from which they were extracted.