You can write a web page in Windows Notepad, but you will not want to for long. A code editor understands the languages you type and turns that knowledge into help:
it checks syntax as you type and underlines errors before the browser sees them;
it suggests element names, CSS properties and JavaScript methods, and expands abbreviations into whole blocks;
it colors code by meaning, so a missing quote or bracket stands out;
it splits the screen so you can view HTML, CSS and JavaScript side by side;
it formats and indents code automatically, and renames a variable everywhere it is used.
Editors fall into three overlapping groups. Offline editors (Offline Editors) run on your computer and handle real projects. Online editors (Online Editors) run in a browser tab and are ideal for sharing a demo or reproducing a bug. AI-assisted tools (AI-assisted Coding) now sit inside both, completing lines, editing many files at once or running whole tasks as agents. Setting Up VS Code turns Visual Studio Code 550 , the editor used throughout this book, into a complete front-end workstation.