Translation Notice
This article was machine-translated using DeepSeek-R1.

• Original Version: Authored in Chinese by myself
• Accuracy Advisory: Potential discrepancies may exist between translations
• Precedence: The Chinese text shall prevail in case of ambiguity
• Feedback: Technical suggestions regarding translation quality are welcomed

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Date.now() // Get milliseconds from 1970-01-01 to current
Date.UTC(2000, 1, 1) // Get milliseconds from 1970-01-01 to 2000-01-01