JavaScript Hoisting - W3Schools
Variables defined with let and const are hoisted to the top of the block, but not initialized. Meaning: The block of code is aware of the variable, but it cannot be used until it has been declared. Using a let variable before it is declared will result in a ReferenceError.
PHP Variables Scope - W3Schools
The scope of a variable is the part of the script where the variable can be referenced/used. PHP has three different variable scopes: local; global; static
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elem = document.getElementById("demo"); // Find an element. elem.innerHTML = x; // Display x in the element. var x; // Declare x. </script>. </body>. </html>.
JavaScript Let - W3Schools
Let Hoisting. Variables defined with var are hoisted to the top and can be initialized at any time. Meaning: You can use the variable before it is declared:
JavaScript Function Definitions - W3Schools
Hoisting is JavaScript's default behavior of moving declarations to the top of the current scope. Hoisting applies to variable declarations and to function declarations. Because of this, JavaScript functions can be called before they are declared: myFunction (5); function myFunction (y) …
JavaScript Scope - W3Schools
JavaScript has function scope: Each function creates a new scope. Variables defined inside a function are not accessible (visible) from outside the function. Variables declared with var, let and const are quite similar when declared inside a function. They all have Function Scope:
JavaScript Variables - W3Schools
Variables are Containers for Storing Data. JavaScript Variables can be declared in 4 ways: Automatically. Using var. Using let. Using const. In this first example, x, y, and z are undeclared variables. They are automatically declared when first used:
JavaScript Const - W3Schools
Hoisting. Variables defined with var are hoisted to the top and can be initialized at any time. Meaning: You can use the variable before it is declared:
JavaScript Use Strict - W3Schools
The purpose of "use strict" is to indicate that the code should be executed in "strict mode". With strict mode, you can not, for example, use undeclared variables. All modern browsers support "use strict" except Internet Explorer 9 and lower: Directive.
JavaScript Data Types - W3Schools
You can use the JavaScript typeof operator to find the type of a JavaScript variable. The typeof operator returns the type of a variable or an expression: