OK, I'm lost. I'm looking to have a signature pad added to my PHP/JS Tablet/desktop app and store some form of its image into MySQL. I opened the GitHub example and captured the "source code" and put minimal HTML code around it. I loaded that into my Orange Pi Debian 8 server. I called it up using Chrome, but no canvas appears and nothing appears to happen on clicks. Chrome development tool says "Uncaught TypeError: Cannot read property 'querySelector' of null" on the example statement: saveButton = wrapper.querySelector("[data-action=save]"), just at the last "r" of "wrapper". I thought I adjusted my <button...> statements to match, but my cloning of another example went south, apparently. What did I miss capturing? Note I downloaded the jQuery library as it appears to be referenced in the sample code and the Chrome debug tool does rattle through it as I run my script. My cloned script is attached (as .txt). Help, please? This is a volunteer project for a program that encourages and rewards Middle and High School students to became proficient in STEM! Suggestions will be appreciated by many. PS: MySQL data type "Long Text" can handle text much longer than any Browser's URL entry field, hence the toDataURL method would be just fine, once I get to that step! (;- PS2: I love that Chrome IDE (wish I had found it months ago!)