In an approach for optimizing read/write access to a document object model in a web browser, one or more computer processors detect one or more accesses to a first data structure of a document object model. Based on the detected one or more accesses, the one or more computer processors determine whether the first data structure is a highly dynamic part of the document object model. Responsive to determining the first data structure is a highly dynamic part of the document object model, the one or more computer processors trigger a conversion of the first data structure to an access optimized data structure. The one or more computer processors convert the first data structure to an access optimized data structure.