1. A system comprising: at least one processor of a computing device; a memory of the computing device; and at least one module loaded into the memory causing the at least one processor to: map a selection in a browser to a portion in a document object model (DOM) corresponding to the selection, the DOM representing a fetched file obtained from a web server in response to an hypertext transfer protocol (HTTP) request, the selection associated with content from the fetched file, the fetched file differs from the DOM; map the portion in the DOM to a location range in a source file that generated the content in the fetched file; receive updated content from the web server based on alterations made to the source file; and display the selection in the browser concurrently with the altered source file, wherein the displayed selection in the browser includes the updated content.