Common Web Development Errors

This is not an exhaustive list, but some common problems I’ve seen in student submissions.

These are errors that can reduce the quality of your code, and lower your page’s readability and maintainability.

HTML Errors

  • 🚨 errors in HTML validation
  • 🎋 a Document Outline that has untitled sections or a weird structure
  • 📰 HTML isn’t formatted following best standards
  • 🤯 more than one <h1> on a page
  • 🛟 content outside of a sectioning element
  • 🔤 page content in <head>
  • 🚫 using discouraged tags like <br>
  • 🖼️ a page has broken links or images

CSS Errors

  • 🚨 errors in CSS validation
  • 📰 CSS isn’t formatted following best standards
  • 🕸️ unnecessarily complex CSS (e.g. extra classes, redundant declarations, etc)
  • 🔤 poorly named classes (or typos in class names)
  • 📦 missing fixed-width container

Framework Errors

  • ⁉️ files/folders with uppercase characters, spaces, or any punctuation other than a dash or an underscore
  • 🔤 non-semantic names
  • ❎ missing a required component:
    • ✅ an HTML doc named index.html in the root folder
    • ✅ a folder called img that contains all the image and logo files
    • ✅ a folder called css that contains the reset code and any site-specific code
    • ✅ a folder called js
  • 📁 the folder in public_html is not named exactly the same as the last part of the URL you’re trying (e.g. if I’m trying to access dmarsh.dmitstudent.ca/my-page, my folder needs to be named exactly my-page)