demo: fix time lag causing no countdown

[c0dedance]

[中文版模板 / Chinese template]

🤔 This is a ...

• New feature
• Bug fix
• Site / documentation update
• Demo update
• TypeScript definition update
• Bundle size optimization
• Performance optimization
• Enhancement feature
• Internationalization
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🔗 Related issue link

💡 Background and solution

📝 Changelog

Language	Changelog
🇺🇸 English	fix time lag causing no countdown
🇨🇳 Chinese	修复时间滞后导致没有倒计时

☑️ Self Check before Merge

⚠️ Please check all items below before review. ⚠️

• Doc is updated/provided or not needed
• Demo is updated/provided or not needed
• TypeScript definition is updated/provided or not needed
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[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

✅ li-jia-nan
❌ c0dedance
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[KurumiRin]

用new Date(new Date().getFullYear(), 12, 31)替代？否则每年都需要更新

[c0dedance]

用new Date(new Date().getFullYear(), 12, 31)替代？否则每年都需要更新

聪明

[c0dedance]

2022-12-31 24:00:00的表达可能有问题，是否需要一同修改
因为2022-12-31 23:59:59 下一秒=> 2023-01-01 00:00:00

[li-jia-nan]

嗯，24:00:00 改成 23:59:59 吧，年份写死 2023 就行了，demo 里面不用写的很复杂

[li-jia-nan]

然后 <p> 标签外层的 <> 标签好像没用，可以顺便删掉

[c0dedance]

嗯，24:00:00 改成 23:59:59 吧，年份写死 2023 就行了，demo 里面不用写的很复杂

ok，明白了

[li-jia-nan]

还是改成动态的了