What does it mean $ and $$ in javascript?

In JavaScript, the $ and $$ symbols are not special keywords, but they are often used as function names or variables, especially in browser developer tools or popular libraries like jQuery. Their meaning depends on the context in which they’re used.

$ in [removed]

In jQuery: $ is commonly used as a shorthand for jQuery. For example:

  $('#elementId').hide();

 This selects an element with the ID elementId and hides it.

In the browser console (Chrome/Firefox): $ can also be a shorthand for document.querySelector():

  $('div') // selects the first  element

Custom usage: Developers can define their own $ function or variable if it doesn’t conflict with existing ones:

  const $ = (id) => document.getElementById(id);

$$ in [removed]

In browser consoles (like Chrome DevTools): $$ is usually a shorthand for document.querySelectorAll():

  $$('div') // selects all  elements as a NodeList

It returns an array-like list of all elements that match a given CSS selector.

Summary:

• $ → document.querySelector() (or jQuery)
  
• $$ → document.querySelectorAll()
  

These shortcuts are handy for quick DOM access in the browser, but their behavior can change depending on the environment (plain JS, jQuery, or browser tools). So, it’s always good to know what’s defining them in your specific context.