Without JavaScript or CSS, or without mobile Webkit, my site may not look pretty but will still be functional.
I will not unnecessarily tax my users' brains with complicated designs and user interfaces. I will strive to make interactions succinct and minimize mental overhead.
Web Browsers should at minimum properly implement web standards and should be responsive to the advancing web. Web Browser Choice should be separate from picking an operating system. This is especially important for mobile devices.
My content was accessible when full Flash / Flex apps were popular, and I will continue to provide accessible device independent content in the face of App Store ubiquity.
My own developer hardware is not representative of the real world, and will be mindful of limited hardware, poor latency, and low bandwidth situations.
Especially when considering file formats and codecs for images, audio, or video.
It is not just about helping users that may have trouble differentiating colors or difficulty reading small fonts, but is about providing comprehensive access for users that may prefer to use either the keyboard or the mouse; in providing a clean print friendly format; in providing content to devices of varying technological capabilities.
I will contribute workarounds, fixes, and document issues that may help others. I will file bugs at the source with the web browser’s bug tracker.
I will better myself not just in math and code, but also in art, music, design, and usability.
I understand that I cannot learn everything and will be mindful of what I do not know.
I will take care to use approaches that will be compatible with current and future web browsers, including preference for feature detection over user agent sniffing when it does not violate rules #1 or #5.
I will be mindful of overzealous CSS specificity, overuse of CSS !important, the global JavaScript namespace, as well as numerous browser implementation quirks.
Whether it be a big choice between a full stack framework and a simple DOM-centric library, or even the simple choice between CSS and JavaScript to solve a task, I will educate myself on the mistakes of those before me to make the correct choice for my project.
I will properly escape my output and code to prevent XSS and CSRF. I will not store sensitive information in Cookies, and will use HTTPS where appropriate. I will be responsive in correcting issues that may cause harm to applications I have created.