DevTools Overview
Chrome DevTools is a set of web developer tools built directly into the Google Chrome browser. It helps you edit pages on-the-fly and diagnose problems quickly.
Key Features
- Elements Panel: Inspect and modify DOM/CSS
- Console Panel: View logs and run JavaScript
- Sources Panel: Debug JavaScript
- Network Panel: Monitor network activity
- Performance Panel: Analyze runtime performance
- Memory Panel: Profile memory usage
- Application Panel: Inspect storage and service workers
Common Use Cases
Debugging
Set breakpoints and step through JavaScript code.
Responsive Design
Test websites on different device sizes.
Performance Optimization
Identify and fix performance bottlenecks.
Security Analysis
Check for mixed content and other security issues.
Example Usage
// Example DevTools Console commands
// Select DOM elements
const header = document.querySelector('header');
const buttons = $$('button'); // Shorthand for querySelectorAll
// Monitor events
monitorEvents(window, 'resize');
unmonitorEvents(window, 'resize');
// Performance measurement
console.time('myOperation');
// Some operation here
console.timeEnd('myOperation');
// Copy to clipboard
copy(document.documentElement.outerHTML);
// Advanced querying
const largeImages = [...document.images]
.filter(img => img.naturalWidth > 500)
.map(img => img.src);
// Debugging helper
debugger; // Pauses execution if DevTools is open
// Store as global variable (right-click in console)
// temp1 = $0