Java script variable question

Question

What is the difference between a variable in java script declared with "var" keyword and without using var keyword in .net .aspx page??

Ranjit Powar · Answer

There are two ways to create global variables in javascript 1. Declare variable outside of all functions as below var x=1; function F1 ( ) { } function F2 ( ) { } 2. If you want to declare global variable inside function then define it with var keyword as below function F1 ( ) { x=1; } function F2 ( ) { } In your below script you create y variable without var keyword so it becomes global variable and other functions can also access it, but z is created with var keyword so it is local variable. This is the difference between these two variables. function x ( ) { y = 1 ; var z = 2 ; } For more information check http://www.w3schools.com/js/js_scope.asp If it helps you, select it as correct answer.

Vivek Kumar · Answer

when we are using var keyword in C# that means we are using Implicit type and type of variable declared is decided by the compiler at compile time. It must be need to initialize at the time of declaration. We declare a JavaScript variable with the var keyword like below var a = 5; var b = 6; var c = x + y; var d = "name"; --------------------------------------------------- If this post helps you, mark it as answer

Amit Kumar Singh · Answer

hey Chandan, In JavaScript: When you use "var" , you are instantiating (or overwriting) a variable in the current scope. This will also prevent access of variables named the same in higher scope, within the current scope. In your first example, 'a' is being instantiated and set within the function scope. In your second example, 'a' is being set outside the function scope (most likely window.a). With var : var a = "A" ( function (){ var a = "B" alert ( a ) //B })() alert ( a ); //A Without var : var a = "A" ; ( function (){ a = "B" alert ( a ) //B })() alert ( a ) //B In Asp.Net: 1. It can store any type of value but It is mandatory to initialize var types at the time of declaration. 2. It is type safe i.e. Compiler has all information about the stored value, so that it doesn't cause any issue at run-time. 3. Var type cannot be passed as method argument and method cannot return object type. Var type work in the scope where it defined 4. No need to cast because compiler has all information to perform operations.

Abhay Shanker · Answer

Var is an implicit type. It aliases any type. var i = 10; // implicitly typed int i = 10; //explicitly typed you can also check below urls http://www.programmerinterview.com/index.php/javascript/javascript-how-var-works/ http://www.w3schools.com/js/js_variables.asp

Chandan Kumar Sahoo · Answer

Hi reader.Let me explain in details.. I am declaring a variable in javascript only function x ( ) { y = 1 ; var z = 2 ; } here in this above example we have two variable y and z. y is declared with out var key word. z is declared with var key word. what is the difference between these two variable ?

Rajeesh Menoth · Answer

Hi, .Net also using var keyword. More details refer the following article : http://www.c-sharpcorner.com/UploadFile/5ef30d/var-keyword-in-C-Sharp-programming/

Krishna Rajput Singh · Answer

Hello Chnadna Kumar Sahoo Thanks for writing below links i hope helpful for u..:) http://www.w3schools.com/js/js_variables.asp https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Statements/var http://www.tutorialspoint.com/javascript/javascript_variables.htm http://www.wikihow.com/Declare-a-Variable-in-Javascript if answer find helpful please mark answer as correct Special thanks c-sharpconer