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What is the lifetime of JavaScript variables?
The lifetime of a JavaScript variable begins when it is declared −
var rank;
A local variable will be visible only within a function where it is defined. Function parameters are always local to that function.The completion of a function deletes the local variable.
A global variable has a global scope which means it can be defined anywhere in your JavaScript code. Global variables delete when the web browser is closed. However if a new page is loaded in the same browser window, then it remains.
Here’s the usage of global variables −
Example
You can try to run the following code to learn how to work with a scope of variables in JavaScript
<html>
<body onload = checkscope();>
<script>
<!--
var myVar = "global"; // Declare a global variable
function checkscope( ) {
var myVar = "local"; // Declare a local variable
document.write(myVar);
}
//-->
</script>
</body>
</html>
Updated on: 15-Jun-2020
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