Non-transitory physical computer storage comprising computer-executable instructions stored thereon that, when executed by one or more processors, are configured to implement a process of executing a first tag container and a second tag container of a content page, the content page comprising a first version of a first page element and a second page element, the first page element being positioned in a first portion of a body section of the content page and the second page element being positioned in a second portion of the body section different from the first portion, wherein the process comprises:
- prior to loading the body section for display in a browser, synchronously executing the first tag container so that loading of the body section for display in the browser is prevented until execution of the first tag container is completed,
- wherein said synchronously executing the first tag container comprises:
- requesting a first script from a first server via a computer network according to first container instructions of the first tag container,
- receiving the first script via the computer network, and
- executing the first script so that, according to first script instructions of the first script, the first version of the first page element is hidden from display by the browser upon loading of the body section for display in the browser;
- loading the body section for display in the browser so that the second page element is loaded and presented as visible by the browser and, according to the first script instructions, the first version of the first page element is loaded and hidden from display by the browser;
- and
- asynchronously executing the second tag container comprising:
- requesting a second script from a second server via the computer network according to second container instructions of the second tag container,
- receiving the second script via the computer network, and
- executing the second script so that, according to second script instructions of the second script, a second version of the first page element is loaded and presented as visible by the browser in place of the first version of the first page element that was loaded and hidden from display by the browser.