中文译文
使用 HTML5、CSS3、JavaScript 和一个可靠的汇率 API 开发一个功能全面的货币转换器。创建一个简洁、直观的界面，包含醒目的输入字段和货币选择器。实现实时汇率，并带有显示数据新鲜度的时间戳指示器。支持 170 多种全球货币，包括加密货币，并提供适当的符号和格式。维护一个带有时间戳和汇率信息的转换历史记录。允许用户收藏常用货币对以便快速访问。生成可自定义日期范围的交互式历史汇率图表。使用缓存的汇率实现离线功能，并提供清晰的过期指示器。添加一个内置计算器，用于复杂转换和算术运算。为目标汇率创建汇率提醒，并可选配通知。在可用时，包含不同提供商汇率的并排比较。支持以多种格式（PDF、CSV、JSON）打印和导出转换结果。
English original
Develop a comprehensive currency converter using HTML5, CSS3, JavaScript and a reliable Exchange Rate API. Create a clean, intuitive interface with prominent input fields and currency selectors. Implement real-time exchange rates with timestamp indicators showing data freshness. Support 170+ global currencies including crypto with appropriate symbols and formatting. Maintain a conversion history log with timestamps and rate information. Allow users to bookmark favorite currency pairs for quick access. Generate interactive historical rate charts with customizable date ranges. Implement offline functionality using cached exchange rates with clear staleness indicators. Add a built-in calculator for complex conversions and arithmetic operations. Create rate alerts for target exchange rates with optional notifications. Include side-by-side comparison of different provider rates when available. Support printing and exporting conversion results in multiple formats (PDF, CSV, JSON).