A system for rendering of dynamic webpage content, comprising: a web browser script operating on a web browser comprising a first plurality of programming instructions stored in a memory of, and operating on a processor of, a first networked computer, wherein the first plurality of programming instructions, when operating on the processor of the first networked computer, cause the first networked computer to: receive annotated content and resources for rendering of a webpage from a first party content provider; request complete modification rules for rendering dynamically modifiable elements of the annotated content from a third party content provider; receive incomplete modification rules for rendering of the annotated content from the third party content provider; render the webpage using the incomplete modification rules; request and receive asynchronous transmission of the complete modification rules from the third party content provider; and render the webpage using the complete modification rules; and a gateway comprising a second plurality of programming instructions stored in a memory of, and operating on a processor of, a second networked computer, wherein the second plurality of programming instructions, when operating on the processor of the second networked computer, cause the second networked computer to: detect the request for complete modification rules from the web browser operating the web browser script to the third party content provider; initiate a timer with a limit; when the timer reaches the limit, request incomplete modification rules from the third party content provider, the incomplete modification rules comprising a generated portion of the complete modification rules; transmit the incomplete modification rules to the web browser operating the web browser script. a web browser script operating on a web browser comprising a first plurality of programming instructions stored in a memory of, and operating on a processor of, a first networked computer, wherein the first plurality of programming instructions, when operating on the processor of the first networked computer, cause the first networked computer to: receive annotated content and resources for rendering of a webpage from a first party content provider; request complete modification rules for rendering dynamically modifiable elements of the annotated content from a third party content provider; receive incomplete modification rules for rendering of the annotated content from the third party content provider; render the webpage using the incomplete modification rules; request and receive asynchronous transmission of the complete modification rules from the third party content provider; and render the webpage using the complete modification rules; and receive annotated content and resources for rendering of a webpage from a first party content provider; request complete modification rules for rendering dynamically modifiable elements of the annotated content from a third party content provider; receive incomplete modification rules for rendering of the annotated content from the third party content provider; render the webpage using the incomplete modification rules; request and receive asynchronous transmission of the complete modification rules from the third party content provider; and render the webpage using the complete modification rules; and a gateway comprising a second plurality of programming instructions stored in a memory of, and operating on a processor of, a second networked computer, wherein the second plurality of programming instructions, when operating on the processor of the second networked computer, cause the second networked computer to: detect the request for complete modification rules from the web browser operating the web browser script to the third party content provider; initiate a timer with a limit; when the timer reaches the limit, request incomplete modification rules from the third party content provider, the incomplete modification rules comprising a generated portion of the complete modification rules; transmit the incomplete modification rules to the web browser operating the web browser script. detect the request for complete modification rules from the web browser operating the web browser script to the third party content provider; initiate a timer with a limit; when the timer reaches the limit, request incomplete modification rules from the third party content provider, the incomplete modification rules comprising a generated portion of the complete modification rules; transmit the incomplete modification rules to the web browser operating the web browser script.