Web page loads are slow due to intrinsic inefficiencies in the page load process. Our study shows that the inefficiencies are attributable not only to the contents and structure of the Web pages (e.g., three-fourths of the CSS resources are not used during the initial page load) but also the way that pages are loaded (e.g., 15% of page load times are spent waiting for parsing-blocking resources to be loaded).

To address these inefficiencies, this paper presents Shandian (which means lightening in Chinese) that restructures the page load process to speed up page loads. Shandian exercises control over what portions of the page gets communicated and in what order so that the initial page load is optimized. Unlike previous techniques, Shandian works on demand without requiring a training period, is compatible with existing latency-reducing techniques (e.g., caching and CDNs), supports security features that enforce same-origin policies, and does not impose additional privacy risks. Our evaluations show that Shandian reduces page load times by more than half for both mobile phones and desktops while incurring modest overheads to data usage.