- js/confirm-close.html: stackoverflow.com/questions/7317273/warn-user-before-leaving-web-page-with-unsaved-changes
- web-cheat/js-image-load.html: load an image from JavaScript dynamically: stackoverflow.com/questions/226847/what-is-the-best-javascript-code-to-create-an-img-element
- web-cheat/js-image-load-viewport.html: load an image from JavaScript dynamically when it would become visible on the viewport: stackoverflow.com/questions/2321907/how-do-you-make-images-load-only-when-they-are-in-the-viewport
- html/img-load-lazy.html: stackoverflow.com/questions/2321907/how-do-you-make-images-load-lazily-only-when-they-are-in-the-viewport/57389607#57389607
- web-cheat/esm.html: ESM modules
- js/keydown.html: stackoverflow.com/questions/16006583/capturing-ctrlz-key-combination-in-javascript
External libraries
- Text editors
- Interactive HTML table sorting
This section talks about solvers/simulators dedicated solving the wave equation. Of course, any serious solver will likely be able to solve a wider range of PDE, so this section contains mostly fun toys. For more serious stuff see: Section "PDE solver".
JavaScript toy solvers:
- jtiscione.github.io/webassembly-wave/index.html circular domain, create waves with mouse click
- dionyziz.com/graphics/wave-experiment/ with useless 3D WebGL visualization :-), waves with mouse click. Solving itself done on CPU, not GPU.
The wave equation can be seen as infinitely many infinitesimal coupled oscillators by 
Ciro Santilli 40 Updated 2025-07-16
Ciro Santilli 40 Updated 2025-07-16TODO confirm, see also: coupled oscillators. And then this idea can be used to define/motivate quantum field theory in terms of quantum harmonic oscillators with second quantization.
- youtu.be/SMmFgIEGYtw?t=324 Quantum Field Theory 2a - Field Quantization I by ViaScience (2018)
Start with: Section "String polarization".
Then go to: Section "Polarization of light".
Examples:
- mechanical resonance, notably:
- pipe instruments
- electronic oscillators, notably:
- LC oscillator, and notably the lossy version RLC circuit
Perhaps a key insight of resonance is that the reonant any lossy system tends to look like the resonance frequency quite quickly even if the initial condition is not the resonant condition itself, because everything that is not the resonant frequency interferes destructively and becomes noise. Some examples of that:
- striking a bell or drum can be modelled by applying an impuse to the system
- playing a pipe instrument comes down to blowing a piece that vibrates randomly, and then leads the pipe to vibrate mostly in the resonant frequency. Likely the same applies to bowed string instruments, the bow must be creating a random vibration.
- playing a plucked string instrument comes down to initializing the system to an triangular wave form and then letting it evolve. TODO find a simulation of that!
Another cool aspect of resonance is that it was kind of the motivation for de Broglie hypothesis, as de Broglie was kind of thinking that electroncs might show discrete jumps on atomic spectra because of constructive interference.
eigenvalue problem of Laplace's equation.
In informal contexts, it usually refers to the phase of ice observed in atmospheric pressure, Ice Ih.
There are unlisted articles, also show them or only show them.