Java Reference
In-Depth Information
assigning Variables the Values of Other Variables
trY it out
Let's look at another example, this time assigning variables the values of other variables.
1.
Type the following code into your text editor and save it as
ch2_example2.html
:
<!DOCTYPE html>
<html lang
=
"en">
<head>
<title>Chapter 2, Example 2</title>
</head>
<body>
<script>
var string1
=
"Hello";
var string2
=
"Goodbye";
alert(string1);
alert(string2);
string2
=
string1;
alert(string1);
alert(string2);
string1
=
"Now for something different";
alert(string1);
alert(string2);
</script>
</body>
<html>
2.
Load the page into your browser, and you'll see a series of six
alert
boxes appear.
3.
Click OK on each
alert
box to see the next alert. The first two show the values of
string1
and
string2
—
Hello
and
Goodbye
, respectively. Then you assign
string2
the value that's in
string1
. The next two
alert
boxes show the contents of
string1
and
string2
; this time both
are
Hello
.
4.
Finally, you change the value of
string1
. Note that the value of
string2
remains unaffected. The
final two
alert
boxes show the new value of
string1
(
Now for something different
) and the
unchanged value of
string2
(
Hello
).
The first thing you do in the script block is declare your two variables:
string1
and
string2
. However,
notice that you have assigned them values at the same time that you have declared them. This is a
shortcut, called
initializing
, that saves you typing too much code:
var string1
=
"Hello";
var string2
=
"Goodbye";
Note that you can use this shortcut with all data types, not just strings. In the next two lines you use
the
alert()
function to show the current value of each variable to the user:
alert(string1);
alert(string2);