📖 PDF 阅读器（在线查看）PDF Reader (Online Viewer)
在浏览器里直接打开和阅读 PDF：翻页、跳到指定页、适合宽度/整页/固定比例缩放、旋转、全文查找（列出每处结果和所在页）、书签目录跳转、查看文档信息、复制当前页文字；支持键盘翻页和加密 PDF，文件不上传。Open and read a PDF right in your browser: page through it, jump to a page, zoom to fit width, fit page or a fixed percentage, rotate, search the full text (every match listed with its page), jump via bookmarks, view document info and copy the current page's text. Keyboard paging and password-protected PDFs are supported; nothing is uploaded.
使用说明与常见问题How-to & FAQ
「PDF 阅读器（在线查看）」是什么？What is the PDF Reader (Online Viewer) tool?
在浏览器里直接打开和阅读 PDF：翻页、跳到指定页、适合宽度/整页/固定比例缩放、旋转、全文查找（列出每处结果和所在页）、书签目录跳转、查看文档信息、复制当前页文字；支持键盘翻页和加密 PDF，文件不上传。Open and read a PDF right in your browser: page through it, jump to a page, zoom to fit width, fit page or a fixed percentage, rotate, search the full text (every match listed with its page), jump via bookmarks, view document info and copy the current page's text. Keyboard paging and password-protected PDFs are supported; nothing is uploaded.
如何使用「PDF 阅读器（在线查看）」？How do I use the PDF Reader (Online Viewer) tool?
在「PDF 阅读器（在线查看）」中，选择或拖入文件，按需设置「页码」、「缩放」、「查找」等选项，然后点击「旋转 90°」、「复制本页文字」、「查找」按钮即可。加密的 PDF 选好后会先出现「打开密码」栏和「打开」按钮，输入密码点「打开」后再继续。In the PDF Reader (Online Viewer): Choose or drop your files, set "Page", "Zoom", "Find", then click "Rotate 90°", "Copy page text", "Search". For an encrypted PDF, a Password field and an Open button appear after you choose it — enter the password and click Open first.
缩放比例 100% 是什么意思？What does 100% zoom mean?
100% 表示按 PDF 的实际尺寸显示（1 英寸 = 96 个屏幕像素，与常见 PDF 阅读器一致）；“适合宽度”让页面宽度占满查看区，“整页”让整页都能在窗口中显示。100% shows the PDF at its real size (1 inch = 96 screen pixels, the same convention as common PDF viewers). Fit width makes the page fill the viewer's width, and Fit page makes the whole page visible in the window.
查找支持什么？How does Find work?
在 PDF 的文字层中查找，不区分大小写，连续空白按一个空格处理；结果列出每处匹配所在的页码和上下文，点击即可跳到该页。最多列出前 500 处，但总数会完整统计。扫描件没有文字层，无法查找。It searches the PDF's text layer, ignoring case and treating runs of whitespace as one space. Each match is listed with its page and surrounding text; click it to jump to that page. Up to 500 matches are listed, but the total count is always complete. Scanned PDFs have no text layer and can't be searched.
可以用键盘翻页吗？Can I use the keyboard?
可以。焦点不在输入框时，按 → 或 PageDown 下一页，← 或 PageUp 上一页，Home 回到第一页，End 跳到最后一页；在“页码”框输入页码后按回车即可跳转。Yes. When the focus isn't in an input box, → or PageDown goes to the next page, ← or PageUp to the previous one, Home to the first page and End to the last. Type a number in the Page box and press Enter to jump there.
旋转会修改文件吗？Does rotating change the file?
不会。旋转和缩放只影响页面在屏幕上的显示，不会修改或保存 PDF；如果要永久旋转页面，请使用“旋转 PDF”工具。No. Rotation and zoom only change how the page is shown on screen; the PDF isn't modified or saved. Use the Rotate PDF tool to rotate pages permanently.
加密的 PDF 可以处理吗？Can it handle password-protected PDFs?
可以。如果 PDF 需要打开密码，会提示你输入；只有权限限制（无打开密码）的文件会自动打开。输出文件不再带密码，如需加密请使用“PDF 加密”工具。Yes. If the PDF needs an open password you'll be asked for it; files with only permission restrictions open automatically. The output is not password-protected — use the Protect PDF tool if needed.
文件会上传到服务器吗？Are my files uploaded?
不会。PDF 在你的浏览器里用 pdf-lib / pdf.js 处理，文件不会离开你的设备，关闭页面后不留存任何数据。No. The PDF is processed in your browser with pdf-lib / pdf.js; files never leave your device and nothing is kept after you close the page.
「PDF 阅读器（在线查看）」免费吗？需要注册吗？Is the PDF Reader (Online Viewer) free? Do I need an account?
「PDF 阅读器（在线查看）」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The PDF Reader (Online Viewer) is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.