Anyone know how this can be done? Would you use a canvas object, svg, jQuery, etc?
Here is a quickly hacked up version of this using SVG I just did. Works well for me on my iPhone. Also works in a desktop browser using normal mouse events.
The options already listed are very good, however here a few more on this topic that I've researched and came across.
1) http://perfectionkills.com/exploring-canvas-drawing-techniques/
2) http://mcc.id.au/2010/signature.html
3) https://zipso.net/a-simple-touchscreen-sketchpad-using-javascript-and-html5/
And as always you may want to save the canvas to image:
http://www.html5canvastutorials.com/advanced/html5-canvas-save-drawing-as-an-image/
good luck and happy signing
Perhaps the best two browser techs for this are Canvas, with Flash as a back up.
We tried VML on IE as backup for Canvas, but it was much slower than Flash. SVG was slower then all the rest.
With jSignature ( http://willowsystems.github.com/jSignature/ ) we used Canvas as primary, with fallback to Flash-based Canvas emulator (FlashCanvas) for IE8 and less. Id' say worked very well for us.
Another OpenSource signature field is https://github.com/applicius/jquery.signfield/ , registered jQuery plugin using Sketch.js .
A canvas element with some JavaScript would work great.
In fact, Signature Pad (a jQuery plugin) already has this implemented.
Here's another canvas based version with variable width (based on drawing velocity) curves: demo at http://szimek.github.io/signature_pad and code at https://github.com/szimek/signature_pad.