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Test Examples.. Predict the output. Run the code. If you are not correct, trace the code again. Get Help if needed.
<?xml version = "1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dt d">
<!-- Fig. 10.7: scoping.html -->
<!-- Local and Global Variables -->
<html xmlns = "http://www.w3.org/1999/xhtml">
<head>
<title>A Scoping Example</title>
<script type = "text/javascript">
<!--
var x = 1; // global variable
function start()
{
var x = 5; // variable local to function start
document.writeln( "local x in start is " + x );
functionA(); // functionA has local x
functionB(); // functionB uses global variable x
functionA(); // functionA reinitializes local x
functionB(); // global variable x retains its value
document.writeln(
"<p>local x in start is " + x + "</p>" );
}
function functionA()
{
var x = 25; // initialized each time
// functionA is called
document.writeln( "<p>local x in functionA is " +
x + " after entering functionA" );
++x;
document.writeln( "<br />local x in functionA is "
+ x + " before exiting functionA"
+ "</p>" );
}
function functionB()
{
document.writeln( "<p>global variable x is " + x +
" on entering functionB" );
x *= 10;
document.writeln( "<br />global variable x is "
+ x + " on exiting functionB"
+ "</p>" );
}
// -->
</script>
</head>
<body onload = "start()"></body>
</html>
Scoping #2 Test Prep
<?xml version = "1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dt d">
<!-- Fig. 10.7: scoping.html -->
<!-- Local and Global Variables -->
<html xmlns = "http://www.w3.org/1999/xhtml">
<head>
<title>A Scoping Example</title>
<script type = "text/javascript">
<!--
var x = 1;
var y = 4;
var z = 5;
function start()
{
var x = 9;
document.writeln( "values are " + x + y + z);
functionA();
document.writeln( "<p>values are " + x + y + z + "<p>");
functionB();
document.writeln( "<p>values are " + x + y + z + "<p>");
}
function functionA()
{
var z = 6;
document.writeln( "<p>Avalues are " + x + y + z + "<p>");
x++;
functionB();
document.writeln( "<p>Avalues are " + x + y + z + "<p>");
}
function functionB()
{
var y = 3;
document.writeln( "<p>Bvalues are "+ x + y + z + "<p>");
x=x+2;
z++;
document.writeln( "<p>Bvalues are " + x + y + z + "<p>");
}
// -->
</script>
</head>
<body onload = "start()"></body>
</html>
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