When we declare a variable, then it has a local scope and a global scope. We can define a variable anywhere in our script. When we declare a variable in JavaScript, we can assign a value to it at the time of declaration or later. Here is an example:
_xyz123; // variable declared without assigning a value to it varabc = "Star"; //variable declared while assigning a value to it
In JavaScript, a variable is defined by a dollar sign the same as in query. In JavaScript, we create variables dynamically using the var keyword. Every variable has a name and a value associated with it. These values can be of any type, such as number, array, string, and so on. A variable name could be a combination of characters and numbers. Here is an example:
(a==undefined){
a=5}A variable that is declared outside a function is a global variable having a global scope. This means that it can be accessed from anywhere within a script.