0_variables.js

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//* Values and Variable in JavaScript
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//* In JavaScript, values and variables are fundamental concepts that form the basis of programming.

//* Values:  A value is a piece of information that a program can work with. It can be a number, text, true/false, or more complex data.

//* Variables: A variable is a container that holds a value. It has a name and can be used to store and manipulate data in a program.

// console.log("welcome to best js course ");

// var myAge = 30;
// console.log(myAge);

//! Let's test
var my_firstName = "John";
//? Explanation: This is a valid variable name. It starts with a letter, and the subsequent characters include letters, numbers, and an underscore. Follows JavaScript naming rules.

var _myLastName$ = "Doe";
//? Explanation: This is a valid variable name. It starts with an underscore, and the subsequent characters include letters, numbers, and a dollar sign. Follows JavaScript naming rules.

var 123myAge = 25;
//? Explanation: This is not a valid variable name. It starts with a number, which is not allowed as per JavaScript naming rules. Variable names cannot begin with a digit.

var $cityName = "New York";
//? Explanation: This is a valid variable name. It starts with a dollar sign, and the subsequent characters include letters. Follows JavaScript naming rules.

var my@Email = "john@example.com";
//? Explanation: This is not a valid variable name. It includes the special character '@', which is not allowed in JavaScript variable names. Only letters, numbers, underscores, and dollar signs are allowed.