v148 · HTML · Performance

Bandwidth Savings Lab

A simulated news feed with 12 video and audio elements. Toggle loading="lazy" globally, adjust the network throttle, and watch the bandwidth budget drop. Each element shows its load state and estimated bytes.

Controls

loading="lazy"
Network speed
4G
Simulate scroll
Reset

Network budget

Data transferred
0 MB of 60 MB total

Savings calculator (lazy vs eager)

💾
0 MB
bandwidth saved
🌱
0 g CO₂
CO₂ equivalent saved
0 s
time saved on 3G

Simulated news feed (12 media elements)

Element-by-element load table

# Type State Est. size Bytes loaded Viewport dist. Priority

see also

implementation reference

Need the exact API surface, compatibility boundaries, errors, lifecycle, and source links? Read the matching gendn reference ↗