为什么要先阅读指南
很多工具看起来很简单，但实际使用时会遇到单位、时区、文件格式、字符限制、二维码扫描、密码安全或正则边界等问题。指南会说明如何检查结果、避免误用，并把你带到对应的工具页面。
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指南
在线工具的实用工作流指南。
学习如何使用开发者工具、写作工具、图片工具、计算器、转换器和生成器，并避免常见错误。
如何在提交作文前统计字数
提交作文前先检查字数、字符数、段落结构和阅读时间，避免超过作业限制。
阅读指南 →指南如何为社交媒体和网页调整图片尺寸
学习如何根据平台比例调整图片尺寸，并在发布前检查清晰度与文件大小。
阅读指南 →指南如何为链接创建并测试二维码
生成二维码后要测试扫描、检查链接、尺寸和错误修正等级。
阅读指南 →指南社交媒体文字长度限制检查指南
发布标题、简介和帖子前，使用字符统计工具检查长度与可读性。
阅读指南 →指南如何计算百分比变化
用清晰步骤计算上涨、下降、折扣和增长率，避免公式混淆。
阅读指南 →指南如何生成强密码并安全保存
生成长而唯一的密码，并使用可信密码管理器保存。
阅读指南 →指南如何在使用前测试正则表达式
用示例文本、flags、捕获组和边界情况测试正则表达式。
阅读指南 →指南如何安全解码 JWT 但不信任它
理解 JWT 解码、签名验证、exp 时间戳与 token 泄露风险。
阅读指南 →指南如何创建 SEO 友好的 URL Slug
从标题生成简短、稳定、可读的 URL slug，并避免关键词堆砌。
阅读指南 →指南如何计算 BMI 并理解结果
了解 BMI 公式、分类限制以及为什么它不能替代医学建议。
阅读指南 →指南如何计算贷款月供和利息
用贷款金额、利率和期限估算月供、总利息和总还款。
阅读指南 →指南如何为网站选择颜色
选择主色、记录 HEX/RGB/HSL，并在设计中检查对比度。
阅读指南 →指南如何转换 KB、MB 和 GB 文件大小
理解十进制与二进制文件单位，估算上传、存储和带宽限制。
阅读指南 →指南如何裁剪并压缩网页图片
先裁剪再调整尺寸和压缩，保持主体清晰并降低文件大小。
阅读指南 →指南发送 API 请求前如何验证 JSON
在调用 API 前检查 JSON 语法、必填字段、转义格式和安全示例，减少请求失败。
阅读指南 →指南JSON 格式化、验证器和 Linter 有什么区别
比较 JSON 格式化、语法验证和风格检查，判断什么时候只需要整理可读性，什么时候需要更严格检查。
阅读指南 →指南如何安全调试 Webhook Payload
用脱敏示例、JSON 格式化、字段检查和时间戳转换调试 Webhook，避免泄露客户或生产数据。
阅读指南 →指南如何测试邮箱、URL 和 ID 的正则表达式
用正例、反例和边界样本测试邮箱、URL、SKU、ID 和日志字段正则。
阅读指南 →指南JavaScript 正则和 Python 正则的区别
了解 flags、分组、Unicode、lookaround 和运行环境差异，避免浏览器测试结果直接套用到后端。
阅读指南 →指南JWT exp、iat、iss、aud Claims 说明
理解 JWT 常见 claims 的含义，并区分解码、过期时间检查和真正的服务端验证。
阅读指南 →指南Base64 和 URL 编码有什么区别
比较 Base64 与 URL encoding，判断文本、查询参数、特殊符号和示例数据应该用哪种编码。
阅读指南 →指南Markdown 转 HTML 预览工作流
发布 README、文档、支持文章和博客草稿前，先预览 Markdown 结构、链接、列表和代码块。
阅读指南 →指南HTML、CSS 和 JavaScript 片段整理工作流
整理小段 HTML、CSS、JavaScript 代码，适合文档示例、演示、工单和快速原型。
阅读指南 →指南JPG、PNG 和 WebP 应该选哪种图片格式
比较照片、透明背景、截图、商品图和网页素材适合的图片格式、体积和兼容性。
阅读指南 →指南如何为 Shopify 商品页压缩图片
压缩电商商品图时保留商品细节、颜色和信任感，同时降低页面加载负担。
阅读指南 →指南如何为 Instagram、TikTok、Facebook 和 X 调整图片尺寸
按社交平台比例、尺寸、文件大小和裁切方式准备发布图片。
阅读指南 →指南如何减小图片体积但尽量不损失可见质量
结合裁剪、尺寸调整、格式选择和压缩设置，在发布前检查清晰度。
阅读指南 →指南图片压缩和图片尺寸调整有什么区别
比较降低文件体积、改变像素尺寸和两者结合使用的场景。
阅读指南 →指南电商商品列表图片尺寸建议
规划商品列表图、缩略图和详情图的比例、尺寸、文件大小与一致性。
阅读指南 →指南如何为客服工单裁剪截图
裁剪截图时保留错误信息和必要上下文，同时减少隐私泄露风险。
阅读指南 →指南Meta Description 字符长度指南
发布页面前检查 meta description 长度、可读性、截断风险和搜索意图。
阅读指南 →指南SEO Title Tag 长度指南
检查标题标签长度、关键词位置、品牌后缀和搜索结果可读性。
阅读指南 →指南X / Twitter 字符长度指南
发布短帖前检查链接、emoji、换行和字符限制。
阅读指南 →指南TikTok Caption 长度指南
规划 TikTok 文案 hook、hashtags、CTA 和可读性，避免发布前超长。
阅读指南 →指南YouTube 标题和描述长度指南
检查 YouTube 标题、描述、链接、章节和搜索摘要的长度与可读性。
阅读指南 →指南如何清理从 PDF 和网页复制的文字
移除多余空格、断行、重复行和杂乱格式，把复制内容整理成可用草稿。
阅读指南 →指南字数统计和字符统计应该用哪个
比较论文、SEO 摘要、社交贴文、表单、短信和平台限制适合的统计方式。
阅读指南 →指南URL Slug 用连字符还是下划线
比较 hyphen 和 underscore 在 URL 可读性、一致性、SEO 习惯和长期维护上的差异。
阅读指南 →指南百分比增加和百分比减少公式说明
理解上涨、下降、折扣、增长率和基准值，避免百分比变化公式混淆。
阅读指南 →指南折扣计算器公式说明
学习折扣价、节省金额、税费和最终结账估算的公式与常见舍入问题。
阅读指南 →指南MB 和 MiB 文件大小有什么区别
比较十进制 MB 与二进制 MiB，理解上传限制、存储面板和主机估算差异。
阅读指南 →指南摄氏度转华氏度公式说明
用公式和示例转换摄氏度与华氏度，适合旅行、食谱、课堂和日常温度检查。
阅读指南 →指南公制和英制单位转换指南
比较长度、重量、速度、温度等公制与英制单位，避免旅行、食谱和技术文档中的单位错误。
阅读指南 →指南贷款月供公式说明
理解固定利率贷款月供公式、月利率、期限、总利息以及为什么估算会和贷款机构报价不同。
阅读指南 →指南How to fix invalid JSON: common errors checklist
Fix invalid JSON by checking quotes, commas, brackets, escaping, arrays, objects, and safe browser-side formatting before sending data.
阅读指南 →指南JSON escaped string vs JSON object
Compare JSON escaped strings and JSON objects so API payloads, logs, webhook examples, and nested JSON fields are easier to debug.
阅读指南 →指南Pretty print JSON vs minify JSON
Compare pretty-printed JSON and minified JSON for debugging, documentation, config reviews, payload size, and production API workflows.
阅读指南 →指南JSON array vs JSON object examples
Understand JSON arrays and objects with examples for lists, records, API responses, configuration, and common formatting mistakes.
阅读指南 →指南URL query string encode and decode guide
Encode and decode URL query strings with spaces, symbols, tracking parameters, UTF-8 text, and safe link sharing checks.
阅读指南 →指南Base64URL vs standard Base64
Compare Base64URL and standard Base64 for JWTs, URLs, tokens, padding, plus signs, slashes, and browser-safe examples.
阅读指南 →指南Unix timestamp seconds vs milliseconds
Understand Unix timestamps in seconds and milliseconds with examples for APIs, JWT exp claims, logs, JavaScript dates, and time zones.
阅读指南 →指南JWT decoding vs JWT verification
Compare JWT decoding and verification so authentication debugging does not confuse readable claims with trusted authorization.
阅读指南 →指南Regex lookahead and lookbehind examples
Learn regex lookahead and lookbehind examples for matching context without consuming text, plus browser engine compatibility notes.
阅读指南 →指南Regex greedy vs lazy quantifiers
Compare greedy and lazy regex quantifiers with examples for HTML snippets, logs, delimiters, repeated text, and safer pattern tests.
阅读指南 →指南UUID v4 vs short random ID
Compare UUID v4 and short random IDs for databases, prototypes, test data, logs, collisions, readability, and public identifiers.
阅读指南 →指南HTML formatter vs HTML minifier
Compare HTML formatting and minification for snippets, templates, documentation examples, page speed, and debugging readability.
阅读指南 →指南Why format CSS before debugging layout problems
Format CSS before debugging layout problems so selectors, braces, duplicate declarations, and responsive rules are easier to inspect.
阅读指南 →指南JavaScript minifier for snippets, not production bundles
Use a JavaScript minifier for quick snippets while understanding why production bundles need build tools, testing, source maps, and safer minification.
阅读指南 →指南How to compress an image under 500KB
Compress an image under 500KB by adjusting dimensions, quality, format, cropping, and preview checks before upload.
阅读指南 →指南How to compress an image under 1MB
Compress an image under 1MB for upload forms, ecommerce pages, applications, and social assets while keeping useful visual detail.
阅读指南 →指南How to resize images for Shopify product photos
Resize images for Shopify-style product photos with consistent aspect ratio, sharp detail, thumbnails, zoom views, and file-size checks.
阅读指南 →指南How to resize images for an Instagram carousel
Resize images for Instagram carousel posts by choosing aspect ratio, safe crop zones, consistent dimensions, and final preview checks.
阅读指南 →指南How to resize an image for a TikTok cover
Resize a TikTok cover image with vertical framing, safe text placement, mobile preview, file-size checks, and compression tips.
阅读指南 →指南Transparent PNG vs WebP for product images
Compare transparent PNG and WebP product images for quality, transparency, file size, browser support, and ecommerce performance.
阅读指南 →指南Best image size for Google Shopping product feeds
Plan product image size for Google Shopping-style feeds with clarity, square crops, file weight, background, and policy-safe checks.
阅读指南 →指南How to crop an image square without distortion
Crop an image square without stretching by choosing a center point, preserving the subject, checking edges, and exporting the right format.
阅读指南 →指南Meta title examples by page type
Review meta title examples for tools, guides, SaaS pages, product pages, category pages, and articles with practical character checks.
阅读指南 →指南Meta description examples by page type
Write meta descriptions for tool pages, product pages, categories, guides, SaaS pages, and articles with character checks and intent matching.
阅读指南 →指南App Store description character count guide
Check app store description length, short descriptions, feature bullets, release notes, and platform-specific copy before submission.
阅读指南 →指南SMS character count: GSM vs Unicode
Understand SMS character counting with GSM, Unicode, emoji, accents, segment limits, and byte-related delivery surprises.
阅读指南 →指南How to clean AI-generated text before publishing
Clean AI-generated text by checking repetition, extra spaces, formatting, lists, headings, claims, and final word or character length.
阅读指南 →指南How to remove duplicate lines from keyword lists
Remove duplicate lines from keyword lists, CSV drafts, outreach lists, and research notes while preserving order and checking case sensitivity.
阅读指南 →指南How to generate URL slugs for product pages
Generate product page URL slugs with readable names, variants, separators, lowercase rules, redirects, and ecommerce SEO checks.
阅读指南 →指南Lorem Ipsum for wireframes and mockups
Use Lorem Ipsum placeholder text for wireframes, mockups, landing page layouts, card grids, typography checks, and content planning.
阅读指南 →指南How to count lines in CSV or log text
Count lines in CSV drafts, logs, lists, and copied text while checking empty lines, headers, malformed rows, and pasted formatting.
阅读指南 →指南Percentage points vs percent change
Compare percentage points and percent change with examples for rates, discounts, growth, conversion, surveys, and reports.
阅读指南 →指南Discount stacking calculation guide
Calculate stacked discounts by applying sequential percentages, tax, final price, savings, and common ecommerce checkout mistakes.
阅读指南 →指南Tip calculator split bill examples
Use tip calculator examples for split bills, tax, service charges, rounding, group meals, and per-person totals.
阅读指南 →指南APR vs interest rate for loan calculators
Compare APR and interest rate for loan estimates, monthly payments, fees, disclosures, and why simple calculators may differ from offers.
阅读指南 →指南Loan term length comparison guide
Compare loan term lengths by monthly payment, total interest, repayment timeline, affordability, and scenario assumptions.
阅读指南 →指南BMI metric vs imperial formula
Compare BMI metric and imperial formulas with unit checks, height mistakes, weight inputs, categories, and responsible interpretation.
阅读指南 →指南Age calculator and birthday countdown guide
Calculate exact age, total days, next birthday countdowns, date assumptions, inclusive counting, and common age-calculation mistakes.
阅读指南 →指南Time duration calculator for timesheets
Calculate work durations for timesheets with start times, end times, breaks, overnight shifts, rounding, and audit-friendly notes.
阅读指南 →指南Days between dates: inclusive vs exclusive counting
Compare inclusive and exclusive date counting for deadlines, trips, subscriptions, projects, and common off-by-one mistakes.
阅读指南 →指南Countdown timer for study sessions
Use a countdown timer for study sessions with focus blocks, breaks, classroom timing, task batching, and distraction checks.
阅读指南 →指南How to use stopwatch lap times for practice
Use stopwatch lap times for typing, workouts, presentations, classroom drills, and repeatable practice measurements.
阅读指南 →指南QR code size for print: practical checklist
Choose QR code size for print by checking scan distance, quiet zone, contrast, URL length, error correction, and phone testing.
阅读指南 →指南How to create a QR code for a restaurant menu
Create a QR code for a restaurant menu with final URLs, scan testing, print size, fallback text, and update-friendly workflows.
阅读指南 →指南Password length vs complexity
Compare password length and complexity for generated passwords, passphrases, symbols, password managers, and account safety.
阅读指南 →指南Random number generator for classrooms
Use a random number generator for classroom activities, groups, raffles, examples, fairness, repeatability, and visible range settings.
阅读指南 →指南Unit converter for recipes and cooking
Convert recipe units for metric and imperial cooking with temperature, weight, volume approximations, rounding, and ingredient caveats.
阅读指南 →指南File size upload limit checklist
Check file size upload limits by converting units, comparing MB and MiB, compressing images, and saving original files before retrying.
阅读指南 →指南HEX vs RGB vs HSL color values
Compare HEX, RGB, and HSL color values for CSS, design systems, opacity, lightness changes, and practical color copying.
阅读指南 →指南How to pick a color palette for landing pages
Pick landing page colors with roles, contrast, CTA visibility, brand consistency, HEX/RGB checks, and practical design-system notes.
阅读指南 →指南Typing test WPM and accuracy guide
Understand typing test WPM and accuracy with practice sessions, mistakes, timing, warmups, and realistic progress tracking.
阅读指南 →