Download - Getting started with dev tools (atl)
About me
• Jasjit Singh
• Self-taught developer
• Worked in finance & tech
• Co-Founder Hotspot
• Thinkful General Manager
About us
Thinkful prepares students for web development & data science jobs with 1-on-1 mentorship programs
About you
• A lot of experience
• A little experience
• No experience
Key Topics
• HTML/CSS Live Editing
• Mobile & responsive testing
• Editing with “Sources”
• Using the console
• Javascript Debugging
• Network performance
Setup — Download Chrome
• Standard for developers (Google!)
• Simple & polished
• Mobile & Desktop
• Firefox & Safari are OK
• Avoid Internet Explorer!
What are DevTools?
How do I open DevTools?
• Go to a page in Chrome
• Right Click => Inspect
• Also — Cmd + Shift + I
What are the benefits?
• Inspect Document Object Model (DOM)
• Update HTML/CSS in real-time
• Test responsive and mobile friendliness
• Run Javascript in console
• Test & debug Javascript
• Measure & improve performance
Why live editing for HTML/CSS?
Typical Workflow
• This style (or code) isn’t working!
• Open HTML/CSS/Javascript
• Guess where the problem is
• Make change
• Save change
• Refresh page
• Did it work?
Workflow with DevTools
• This style (or code) isn’t working!
• Open DevTools (“Inspect”)
• Make change
• Did it work?
What am I looking at?
DOM Styles
Live Editing HTML
• Inspect element
• Expand/Collapse
• Edit HTML
• Add attributes
• Click & drag
• Delete
Challenge
• Go to facebook.com
• Change your name to a friend’s name
• Try and change picture
Live Editing CSS
• See computed CSS styles
• CSS for states
• Add CSS properties
• Modify CSS properties
• Remove CSS properties
• Links to CSS source files
Challenge
• Change background to your favorite color
• Add a fun border to the post button
• Delete Newsfeed (advanced)
Sources Features
• Prettify
• Persistent changes
• Local modifications
• Revert
• Save As
Mobile Demo
• Responsive sizes
• Device
• Frame
• Media queries
• Rotate
Console Features
• Interact with page in real-time using Javascript
Console Demo
• Basic JS commands
• Grab/manipulate element
• Quick scrape
Challenge
• Go to https://dream-walker.herokuapp.com/
• Change the title using Javascript in the console
Javascript Debugging is Pain
Debugging Features
• See where Javascript is failing
• Inspect variables
• Step through code slowly
Debugging Demo
• http://samplerdj.com
• Add breakpoint (+ step through)
• Inspect variables
• Pause on caught & uncaught exceptions
Load times are important!
• Yahoo: reducing page load by .4 seconds increased traffic by 9%
• Google: increasing page load times from .4 to .9 seconds decreased traffic by 20%
• Amazon: every .1 second increase in load time decreases sales by 1%
Network Features
• Test load times
• Throttle to different speeds
• See which files are cached or not
• See which files are causing slowdowns
• See file download sequence
• Google PageSpeed!
Network Challenge
• Go to https://dream-walker.herokuapp.com/
• What is page load time?
• What files are causing slowdowns?
• What do you recommend as a fix?
Advanced Topics
• CPU profiling
• Memory profiling
More about Thinkful
• Anyone who’s committed can learn to code
• 1-on-1 mentorship is the best way to learn
• Flexibility matters — learn anywhere, anytime
•We only make money when you get a job
Our Program
You’ll learn concepts, practice with drills, and build capstone projects — all guided by a personal mentor
Our Mentors
Mentors have, on average, 10+ years of experience
Web Development Syllabus
• Frontend Development (HTML, CSS, Javascript)
• Frontend “Frameworks” (React.js)
• Backend Development (Node.js)
• Electives (Python, Ruby, Swift, Angular, UX)
• Computer Science Fundamentals
• Technical interviews + Career prep