JavaScript Tutorial
JavaScript Dates
JavaScript provides the Date object to work with dates and times. It allows you to create, read, modify, and format dates easily.
Creating a Date
Current Date & Time
let now = new Date();
console.log(now);Specific Date
let date = new Date("2025-01-15");Using Date Parameters
let customDate = new Date(2025, 0, 15, 10, 30, 0);
// Year, Month (0-based), Day, Hours, Minutes, Seconds
Month starts from 0 (January) to 11 (December).
Date Methods (Get Values)
let d = new Date();
d.getFullYear(); // Year
d.getMonth(); // Month (0–11)
d.getDate(); // Day
d.getDay(); // Weekday (0–6)
d.getHours(); // Hours
d.getMinutes(); // Minutes
d.getSeconds(); // SecondsSetting Date Values
let d = new Date();
d.setFullYear(2026);
d.setMonth(5); // June
d.setDate(20);
d.setHours(14);Formatting Dates
Convert to String
d.toDateString(); // "Mon Jan 15 2025"
d.toTimeString(); // "10:30:00 GMT+0530"
d.toISOString(); // "2025-01-15T05:00:00.000Z"Locale Date Format
d.toLocaleDateString();
d.toLocaleTimeString();Timestamps
Date.now(); // Current timestamp in millisecondslet timestamp = new Date().getTime();Date Comparison
let d1 = new Date("2025-01-01");
let d2 = new Date("2025-02-01");
console.log(d2 > d1); // true
Date Difference (Days)
let start = new Date("2025-01-01");
let end = new Date("2025-01-10");
let diff = end - start;
let days = diff / (1000 * 60 * 60 * 24);
console.log(days); // 9Common Use Cases
- Show current date/time
- Age calculation
- Countdown timers
- Booking systems
- Logging events
Common Mistakes
- Forgetting month is zero-based
- Comparing date strings instead of Date objects
- Ignoring time zones
Best Practices
- Use toLocaleDateString() for UI
- Use timestamps for calculations
- Always validate date input
- Be aware of time zones