No-Library (pure JS), HTML, CSS, JavaScript
jQuery 3.4.1, HTML, CSS, JavaScript
jQuery 1.11.0, HTML, CSS, JavaScript
Example taken from HTML5 Canvas Tutorials (http://www.html5canvastutorials.com/labs/html5-canvas-scaling-a-drawing-with-plus-and-minus-buttons/)
for use on github issues.
http://stackoverflow.com/questions/14059369/enable-checkbox-if-text-field-is-not-empty-with-inconsistent-id/