← Lab homeThe numbers speak for themselves—500 text blocks, two measurement engines, one unambiguous performance winner.
What It Does
DOM vs Pretext Benchmark is the most analytically useful demo in the showcase. Two identical column layouts display side by side, each containing 500 text blocks. The left side uses classical DOM measurement; the right side uses Pretext. Resize your browser window and watch both sides respond to the layout change. Real-time frame rate counters on each side show the raw numbers. The DOM side struggles to maintain 15 frames per second at 500 blocks; the Pretext side runs at 60fps with headroom remaining. No marketing language is needed. The performance difference isn't subtle optimization—it's the difference between usable and unusable. A ~500x improvement in layout efficiency translates to a fundamental change in what's architecturally possible. This is the demo that converts skeptical engineers into Pretext adopters because it lets them see the difference in their own browser.
Technical Highlights
The benchmark uses identical text content, fonts, and responsive logic on both sides, ensuring the comparison is fair and meaningful. Each text block is styled identically; the only difference is the measurement engine. When the window resizes, both layouts recalculate at the same time. The DOM side queries the browser's layout engine for each measurement, forcing reflow and repaint cycles. Each query blocks JavaScript execution until layout is complete. At 500 elements, these blocks compound dramatically. Pretext computes the same measurements without touching the DOM, applying typographic rules in pure computation. No reflow, no render blocking, no layout thrashing. The frame rate graphs reveal the bottleneck immediately. This demo succeeds because it measures what matters: real-world performance under realistic load, not synthetic microbenchmarks. The numbers are compelling because they're honest.
Pretext APIs Used
| API | Purpose |
|---|---|
| Batch text measurement | Measure 500 blocks with single computation |
| Font metrics | Apply accurate typography at scale |
| Real-time layout recalculation | Update all measurements on window resize |
| Performance profiling | Track frame rate and layout cost |
How to Try It
Visit the DOM vs Pretext Benchmark demo on desktop for the clearest results. Resize your browser window slowly and watch the frame counters on both sides. Notice which side maintains 60fps and which drops to 15fps or lower. Try rapid resizing to stress-test both engines. Try reducing your browser's window to half-width to increase layout pressure, or expand it to a wider dimension to see if either side improves. For the most convincing results, open developer tools and observe the timeline on the DOM side—you'll see layout thrashing events that never appear on the Pretext side. This demo is designed for engineering teams evaluating layout solutions; the performance data speaks louder than any pitch.
Built By
Created by clawsuo-web. View the source on GitHub.
