Browser - Javascript - (Web) Console



The Web Console is a shell embedded in the browser part of the devtool that can:

  • interpret a single line of code at a time REPL
  • and then interact with the page and execute JavaScript.

See also: Javascript - (Firefox) Scratchpad

  • You can add message to the console through Console logging. The console keep a record of every message posted to it on any given page until the page is closed, navigated away from, or refreshed.
  • Each message has a link to the file name with the line number you can navigate to.

The console is implemented as a function of window and its qualified name is window.console.



Web Console > Console Message.

Firefox Console

Css Reflow event.


The Chrome DevTools Console panel is your focal point for direct interaction with a page in real time.

Ctrl + Shift + J or Esc in any other dev tool tab (It opens the Console Drawer)

Chrome Javascript Console

By default, logging and error output from frames or extensions contained within a page will not be output to the Console. An iframe element, for example, would create its own frame context, selectable from the dropdown menu at the top of the console

Documentation / Reference

  • Chrome: go to View > Developer > JavaScript Console (guide)
  • FireFox: go to Tools > Web Developer > Web Console (guide)
  • IE11: go to Tools > Developer Tools > Console icon (guide)
  • Safari: turn on the Develop menu: Preferences > Advanced > Show Develop menu in menu bar go to Develop > Show Web Inspector (guide)

Discover More
Global Namespace Web Console Firefox
Browser - (Window | Tab) (Javascript Global scope)

window: is a javascript object that represents a tab in the whole browser that render a document. is the javascript global scope for the variable in the browser. is part of the web api holds the...
Browser Devtool D3
D3 - Devtool (Browser)

developer tools in the context of D3 development Google Chrome’s developer tools. The top regions inspect: A - the document hierarchy and B - inherited style properties; underneath,...
Chrome Options Request
HTTP - OPTIONS Request Method

OPTIONS is a request method used in CORS procedure (ie the the “pre-flight” request) asking the server for the CORS headers, but without data. Trying to fetch data from ...
Cors Blocked
How to resolve a blockage due to a CORS policy error? A getting started guide

A detailled step by step guide on why you can get a CORS policy violation and how to simply resolve it
Javascript Console Dir
Javascript - (Console) Logging

logging in javascript are functions of the console Console logging permits inspecting a Web application (page). window Level Shows All Shows all console output Errors Only show output from...
Javascript - (Interpreter|Engine|Runtime)

Javascript Interpreter (JavaScript_engineJavaScript engine) is a software which interprets and executes JavaScript code. Javascript can run in two different environment: within a browser or without...
Javascript - Getting Started (Hello World) in the browser

Javascript in the browser getting started page. In a web page, Javascript is modifying the HTML dom (the browser representation of the HTML page). With the Web Dom API, you handle one DOM element at...
Global Namespace Web Console Firefox
Javascript - Global (Object|Namespace|window)

The global namespace is the top space of Javascript that contains the variables. In a browser, it's known as the window. Defining global variables pollutes the common namespace shared by everyone, introducing...
Javascript - Profiler

in Javascript Chrome console - Doc Performance...
Javascript - Shell

Shell in Javascript For a javascript shell: in the browser. See in Java Nashorn - others. See Shells Shells

Share this page:
Follow us:
Task Runner