Front end development best practices
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Slides from 'Back to Basics' quarterly theme presentation @Version 1 covering: general front-end best practice guidelines,HTML markup, CSS, Java Script, Accessibility, Performance, Cross-browser compatibility, Code Reviews and Tools & resources
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Front end development best practices
- 1. Our Awards: Front-end Development Best Practices Back to Basics Karolina Coates, Pádraig Buckley 25/09/2014 Our Awards:
- 2. Agenda General guidelines HTML markup CSS Java Script Accessibility Performance Cross-browser compatibility Code Reviews Tools & resources
- 3. Introduction to Front End Development This is not about forcing you to believe what I believe Image & slide credit: Christian Heilmann
- 4. Introduction This is the standard we expect. Please contribute.
- 6. Introduction General Guidelines Browser Device Resolution
- 7. General Guidelines • All front-end code should display clear separation of presentation, content, and behaviour
- 8. General Guidelines Markup • Markup should be well-formed, semantically correct – Describe the content rather than the way it is presented. – Provide Meaning • Valid – e.g. W3C Validatior – Identify missing tags, broken links Semantic Non-Semantic <form>, <img>, <section> <div>, <span>
- 9. General Guidelines • JavaScript should progressively enhance the experience – Make a static webpage interactive and enhance usability – Load on Demand • Response Times – Test Everything • The environments • The displays
- 11. HTML Mark-up General Guidelines • Doctype – <!DOCTYPE html> • Structure and Outline of a Document • Don’t use tables for layout • Use <p> instead of </br>,  
- 12. HTML 5 General Guidelines • Comment on closing tags to indicate what element you are closing • Continuously Test • Readability vs Compression – Maintenance
- 15. HTML 5 New Form Types • Email, date, range, tel, required • For further info, go to – http://www.w3schools.com/html/html5_intro.asp
- 17. CSS Best Practices • Create a Style guide – Headings – Buttons – Colour Scheme etc.
- 18. CSS General Guidelines – Use External style sheets – Include CSS files in the HEAD of the document – Establish standards for coding style and practices – Ensure consistency across browsers • normalize.css to make rendering more consistent across browsers.
- 19. CSS Inline CSS
- 22. CSS CSS Box Model padding: 20px 80px 10px 40pxmargin: 20px 80px 10px 40px;
- 23. CSS Clearfix
- 24. CSS Clearfix
- 25. CSS Clearfix
- 26. CSS Selectors • Naming conventions – Use a name that describes what it is rather than what it looks like • Classes Vs ID’s • Selectors • .class and #id • Grouping Selectors
- 30. CSS Which CSS rule has a power to override them all?
- 31. CSS !Important Tag • When to use • Never unless they are absolutely necessary • Harder to maintain style sheets
- 32. CSS ! Important Tag • When it can be used – Temporarily fix an urgent problem – Override inline styles
- 33. CSS Inheritance & Cascading • Styles can be inherited from a parent • Overriding styles
- 34. CSS Developing Responsive Applications and many more… google it
- 35. CSS Media Queries • Change styles depending on a number of properties – Size – Resolution – Orientation
- 37. Java Script Should progressively enhance the experience • General Guidelines – Stored in an External .js file – Include at the end of the document – Comment your code and use Whitespace – Formatting of JavaScript Code – Validate your code • http://www.jslint.com/
- 38. Java Script General Guidelines • Never End a Definition with a comma • Use === Comparison – The == comparison operator always converts (to matching types) before comparison. – The === operator forces comparison of values and type:
- 40. Java Script Global Variables • Global Scope Vs Local Scope • Minimize the number of global variables • Local variables are not available outside the function
- 41. Java Script • Variables – Lowercase or camelCase • Name Logically – popUpWindowForAd rather than myWindow • Bad Examples – X1, createNewMemberIfAgeOverTwentyOneAndMoonIsFull
- 42. Java Script Avoid Mixing Technologies
- 43. Java Script Over Reliance on JavaScript
- 44. Java Script Debugging – Can help refine code and loading speed – Use developer tools
- 45. Java Script Scripts • Plugins – plugin.js and script.js – Advantage • Give the site greater functionality/ Dynamic – Disadvantage • Too many plugins can have a negative effect on performance
- 46. Accessibility
- 47. Image credit: Travelbag Ltd (https://www.flickr.com/photos/98585738@N07/10346101216 Accessibility Reality check: Accessibility rights are growing teeth Image credit: Travelbag Ltd https://www.flickr.com/photos/98585738@N07/10346101216
- 48. Accessibility • Web Content Accessibility Guidelines (WCAG) • Ireland Disability Act 2005: Where a public body communicates in electronic form, the communication must be as far as practicable, "accessible to persons with a visual impairment to whom adaptive technology is available" “ • W3C Web Accessibility initiative – Easy Checks: http://www.w3.org/WAI/eval/preliminary
- 49. Accessibility – Easy Checks Page title Image text alternatives ("alt text") <img src="pointer_to_image.png" alt=“describe the meaning of the image"> Correct markup http://validator.w3.org/
- 50. Accessibility – Easy Checks – cont. Color contrast Color Contrast Checker http://webaim.org/resources/contrastchecker/
- 51. Accessibility – Easy Checks – cont. Headings […] etc.
- 52. Accessibility Code checks do not guarantee that people with disabilities will be able to use your website. • Requirements need to be defined by the customer • Train developers and testers to evaluate • Build best practice into development process • Use accessibility evaluation tools • Involve users in evaluating
- 53. Performance
- 54. Performance Follow Yahoo Performance Guidelines • Put stylesheet links at the top (HEAD) • Put scripts at the bottom • Minify JS and CSS files • Automate the two above • Optimise JavaScript execution • Reduce number of HTTP requests – Combine CSS files together – Combine JS scritps – Use CSS sprites – Caching • Use a Content Delivery Network • Reduce image size (px and KB)
- 55. Test it - YSlow, Page Speed, Hammerhead, MSFast, …
- 56. Performance - Image size (px) Live demo
- 57. Performance – Image size (KB) Image formats – JPG vs GIF vs PNG
- 58. Performance Image formats – a quiz! Match a file format with use scenario: Size matters + = ? Size matters + = ? + transparent background = ? Image credit: Huffingtonpost http://www.huffingtonpost.com/2011/05/31/the-hardest-simpsons-quiz-of-all-
- 59. Performance – CSS spritesPerformance – CSS sprites Image credit:Steve Jurvetson https://www.flickr.com/photos/jurvetson/10793760553
- 60. Performance – CSS sprites Image credit: DryBowser455 http://s1037.photobucket.com/user/DryBowser455/media/NyanCatSprite.png.html, Giphy.com =
- 61. Performance – CSS sprites Image credit: Kasey Jean Robinson http://www.kaseyjeanrobinson.com/tech/what-is-a-css-sprite/
- 62. Performance – CSS sprites Image credit: CSS Tricks http://css-tricks.com/css-sprites/
- 63. Performance – CSS sprites Create manually: • SpritePad • ZeroSprites • SpriteCow • … and many more – google it! OR automate: • grunt-spritesmith • node-spritesheet • dr-grunt-svg-sprites • ... and many others.
- 64. Performance • Performance can be subjective • It’s about managing customer’s expectations – agree what’s acceptable. • Communicate performance impact during design phase or changes Things to remember:
- 66. Cross-Browser Compatibility What do we support? There are two major truths when it comes to in-browser experience: 1. Everyone wants the best experience possible (support them all!). 2. Everything added to the page slows it down.
- 67. Cross-Browser Compatibility What do we support?
- 68. Cross-Browser Compatibility Browsers Devices Resolutions Cross-Browser Compatibility Image credit: Gideon https://www.flickr.com/photos/malias/73169727
- 69. Cross-Browser Compatibility Define & communicate what you support • Time • Effort • Cost
- 71. Cross-Browser Compatibility Testing is the key Emulators vs virtual machines vs actual device https://modern.ie Firefox portable apps Opera archive Chome updates itself Devs and testers should have access to the same setup
- 72. Code Reviews
- 73. Code Reviews • It's about mitigating risk • Catches bugs that can affect multiple pages • It’s ‘you time’ and it’s about your professional development Why do it Peer code reviews are the single biggest thing you can do to improve your code - Jeff Atwood (Coding Horror) “
- 74. Final word
- 75. Code Reviews The Internet is a cobweb of different technologies cobbled together with duct tape, string and chewing gum. It's not elegantly designed in any way, because it's more of a growing organism than it is a machine constructed with intent. - Mattias Petter Johansson, Developer at Spotify “
- 76. Image credit: Daniel Levy http://www.bedeliberate.com/use-giants-to-see-further/ -GOOGLE IT
- 78. Tools & Resources • W3C CSS Validation Service • HTML Validation firefox extension • CSS validator Validators Browser Developer Tools • Chrome Developer Tools • IE Developer Tools (F12) • Firefox Firebug • Opera Dragonfly CSS Sprite generators Manual: • SpritePad • ZeroSprites • SpriteCow Automatic: • grunt-spritesmith • node-spritesheet • dr-grunt-svg-sprites • ... and many others. Front-end templates & frameworks • http://cssframeworks.org/ • Bootstrap • HTML5 Boilerplate • Topcoat