#JavaScript
#Global Variables and Local Variables
global and local variables
Variables can be divided into Global Variables and Local Variables according to their scope.
A global variable is a variable declared outside a function and accessible throughout the program.
A local variable is a variable declared within a function that is created when the function is executed and destroyed when the function exits. It cannot be accessed outside the function.
example 1
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>JavaScript</title>
</head>
<body>
<script>
var jbVar = 'Lorem';
function jbFunc() {
var jbVar = 'Ipsum';
}
document.write( jbVar );
</script>
</body>
</html>I set the value of the variable jbVar to Lorem outside the function and Ipsum inside the function. Since I called jbVar outside the function, the value of the global variable
Loremis output.
example 2
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>JavaScript</title>
</head>
<body>
<script>
var jbVar = 'Lorem';
function jbFunc() {
var jbVar = 'Ipsum';
document.write( jbVar );
}
jbFunc();
</script>
</body>
</html>Since I called the value of jbVar inside the function, the value of the local variable
Ipsumis output.
example 3
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>JavaScript</title>
</head>
<body>
<script>
var jbVar = 'Lorem';
function jbFunc() {
jbVar = 'Ipsum';
document.write( jbVar );
}
jbFunc();
document.write( jbVar );
</script>
</body>
</html>Specifying the value of the variable without using var inside the function will change the value of the global variable. therefore,
IpsumIpsumis output.