Choose a published component or a local `.wasm` file. For text components,
type in the text box or paste while the debugger screen has focus. Use `X I`
for input memory, `X O` for output memory, `X R` for the last read, and `X W`
for the last write. Press `M` to switch between memory bytes and the page map.
While examine mode is active, Up and Down Arrow page through memory.
Open the browser console and press a debugger key to see render timings. The
page reports the complete synchronous update, a forced style and layout pass,
and the wait for the next animation frame. To
measure paint and compositing, record the keypress in the browser's Performance
panel. The page adds timestamp markers to that recording. Developer Tools and
console logging add some overhead, so compare several keypresses.
Turn on **Memory thermal** to run
[the memory heat map tool](/docs/qip-interpret-memory-thermal-ktx2) on the same
component and input. It draws one pixel per byte of each 64 KiB page that
`render` touched, 256 bytes per row, with tiles stacked top to bottom. Red is
the instructions spent producing a byte, green is loop iterations, blue is
calls, and alpha is how often it was accessed. Faint grey bytes were loaded
from a data segment or the input but never used. The image covers the whole
run, not the steps so far, and runs again each time the target or input
changes. Hover a pixel to read its tile, offset, and levels. **Absolute scale**
uses a fixed log scale so you can compare runs, and the readout then shows
approximate counts.
Not every QIP component is supported yet. The interpreter accepts modules up
to 1 MiB with no imports, one memory up to 128 MiB, and one fixed `funcref`
table with up to 4,096 entries. It supports active function-index element
segments and typed `call_indirect`, but not table mutation. An unsupported
component shows the reason in the debugger screen.
Download: